When a large amount of nicotinamide (500 mg per kg body weight) was intraperitoneally injected into rats, the ratio of N¹-methyl-4-pyridone-3-carboxamide (4-py) to N¹-methyl-2-pyridone-5-carboxamide (2-py) excretion steeply decreased until 24 hr after injection, then this excretion ratio recovered gradually and returned to the normal level by day 4 after injection. The ratio of 2-py plus 4-py to N¹-methylnicotinamide (MNA) excretion was also decreased steeply by a pharmacological dose of nicotinamide. This ratio decreased until 24 hr after injection; after that time it recovered gradually and returned to the normal level. The rats were killed 24 hr after the injection and the activities of nicotinamide methyltransferase, 2-py forming MNA oxidase, and 4-py forming MNA oxidase in liver were measured. The activity of nicotinamide methyltransferase was slightly increased by a pharmacological dose of nicotinamide but the activities of 2-py forming MNA oxidase and 4-py forming MNA oxidase in the injected group were 45 % and 7 % of normal, respectively. From these results, it was found that the decreased ratios of 4-py to 2-py excretion and of 2-py plus 4-py to MNA excretion were attributed to the changes of the two MNA oxidase activities by a pharmacological dose of nicotinamide. The addition of nicotinamide to the standard assay reaction mixture of 2-py forming MNA oxidase and 4-py forming MNA oxidase did not affect the 2-py and 4-py formation activities.

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A new process for tryptophan production was established using a lipoic acid auxotrophic mutant, Enterobacter aerogenes L-12, which has both pyruvic acid productivity and tryptophanase activity. The process consists of the production of pyruvic acid from glucose by the washed cells and the subsequent conversion of the acid to tryptophan by the tryptophanase itself in the presence of indole and NH₄Cl.
To prepare washed cells of which the tryptophanase activity and the pyruvic acid productivity were both high, it was best to culture the strain in a medium containing 1% Polypepton, 0.2% glucose, 3 μg/l DL-lipoic acid, 0.05% L-tryptophan, and mineral salts. The optimum composition of the reaction mixture for the pyruvic acid production by the washed cells was established. Under these conditions, 17 g/l of pyruvic acid was accumulated from 5% glucose after 36 hr of incubation. Thus, the conversion of the pyruvic acid to tryptophan was done by adding indole, NH₄Cl, pyridoxal-5'-phosphate, Triton X-100, and KOH to adjust the pH to 9.0 to the above reaction mixture. As a result, the pyruvic acid was rapidly converted to tryptophan, and the concentration of 14 g/l was obtained after 36 hr (total 72 hr).

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The half-saturating concentration of ribulose 1, 5-bisphosphate carboxylase/oxygenase (RuBisCO) from Euglena gracilis Z for CO₂ in its activation by CO₂ in the presence of a saturating concentration of MgCl₂ (K_a) was measured by analyzing the partial reversible inactivation of the fully activated enzyme in the medium with dilute CO₂. The K_a of the Euglena enzyme was 12.5 μM. The K_a values were 6.3 μM for the enzyme from soybean, 10.8 μM from maize, 23.3 μM from Scenedesmus obliquus, and 20.8 μM from Anabaena 7120. The activated state of Euglena RuBisCO was stabilized by 6-phosphogluconate, fructose 1, 6-bisphosphate, and 3-phosphoglycerate in the medium containing low concentrations of CO₂. Both fructose 6-phosphate and ATP stimulated inactivation in the medium. NADPH not only stabilized the activated state of the enzyme, but also enhanced the enzyme activity over the full activity measured in the absence of NADPH. NADP⁺ did not nullify the effects of NADPH on the activation at all. The physiological significance of the effects of these photosynthetic metabolites on the activated state of Euglena RuBisCO is discussed.

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A phenoloxidase from spinach leaves was extensively purified to homogeneity. The molecular weight of the purified enzyme was 150, 000 by gel filtration, and 40, 000 by SDS-polyacrylamide gel electrophoresis. The enzyme contained 2 atoms of copper per 150, 000 of molecular weight. The optimum pH of the enzyme action is near 6.5. The enzyme lacks cresolase activity. Km and k₀ were measured for some 4-substituted catechols and oxygen. Log k₀ values for catechols substituted in position 4 by -NO₂, -CHO, -CH₃, -COOH, or -CH₂CH₂COOH were confirmed to fit Hammett relationships (ρ-Values for σ_p and σ_m are - 3.652 and - 4.007, respectively), but not for log Km values. Log(k₀/Km) values for the same substrates were confirmed to have this relationship, but protocatechuic and hydrocaffeic acids deviated from this linearity.

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The covalent attachment of activated polyethylene glycol₂ (PEG₂) of 10, 000 daltons to nonessential groups on a serine proteinase II (SepII) from Aspergillus sojae produced two modified preparations (PEG₂-SepII-S and PEG₂-SepII-L). The molecular weights of PEG₂-SepII-S and PEG₂-SepII-L were about 170, 000 and 280, 000, respectively. The PEG₂-SepII-S lost about 80% of its antigenicity, while the PEG₂-SepII-L completely lost its antigenicity. In comparison of kinetic parameters with SepII there was less than 40% variation in Km, but the values of K_cat towards succinyl-L-leucyl-L-leucyl-L-valyl-L-tyrosine 4-methylcoumaryl-7-amide (Suc-LLVY-MCA) or succinyl-Lalanyl-L-alanyl-L-valyl-L-alanine p-nitroanilide (Suc-AAVA-pNA) decreased to about 70% less than that of SepII. The modified preparations have about 20 % activity towards fibrin hydrolysis and a low affinity for a protein proteinase inhibitor, Streptomyces subtilisin inhibitor (SSI), with a molecular weight of 23, 000, while the preparations have high affinity for a low molecular weight microbial inhibitor, chymostatin. The stoichiometry of the reaction of α₂-macroglobulin (α₂M) with PEG₂-SepII-S showed that PEG₂-SepII-L bound to α₂M in a molar ratio of 1:1. No appreciable differences were observed in the pH stabilities of the modified enzymes and the native one at pH 3.6, while the modified enzymes were more stable than that of the native one at pH 11.5. The two modified preparations were labile at 50°C, but the native enzyme was completely stable at 50°C.

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The effects of furan compounds, which were produced by the reactions of amino acids with sugars, were examined on the mutagenicity of some mutagens. Amino-carbonyl reaction mixtures of Phe and Cys and glucose or fructose in the presence of malic acid at 100°C for 8 hr inhibited the mutagenicity of Trp-P-1 and Benzo[a]pyrene (B[a]P) toward Salmonella typhimurium TA 98 and TA 100. Furan compounds such as 5-hydroxymethyl-2-furfural, 5-methylfurfural, furfural, furfuryl alcohol, furan, 2-acetylfuran and 2-methylfuran also inhibited the mutagenicity of Trp-P-1, B[a]P and 2-aminofluorene toward TA 98 and TA 100 in the presence of S9 mix. The desmutagenic action of these furan compounds varied with the kind of mutagen. Among the furan compounds, 5-hydroxymethyl-2-furfural, furfural and 2-acetylfuran showed high desmutagenicity towards the mutagens used, while the desmutagenicity of furan and 5-methylfurfural was low.

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Partially purified FBPase of B. flavum exhibited Michaelis-Menten kinetics, with Km of 22 μM for Fl, 6P₂, but was inhibited by its substrate, Fl, 6P₂, at more than 30μM. The inhibition reached 76% at 1.0mM. FBPase was also competitively inhibited by AMP, SI, 7P₂, and S7P, the inhibitor constants being 32, 23, and 170μM, respectively. The presence of SI, 7P₂ in B. flavum was suggested by the presence of ATP-dependent S7P kinase and SI, 7P₂ aldolase activities, which corresponded to 27 and 89% of the 6PFK and Fl, 6P₂ aldolase activities, respectively. Transaldolase activity involved in S7P formation was also detected in cell-free extracts. Partially purified PGI showed Kms of 1.4 and 0.54mM in the forward and reverse directions, respectively and was inhibited by E4P. The inhibition was of the mixed type with respect to G6P, with Ki and Ki' of 32 and 260 μM, respectively. None of the metabolites tested inhibited TK. Whereas the specific activities of PGI and 6PFK were not affected by carbon sources in the culture medium, those of FBPase, IPFK, and TK were elevated 2.6, 2.6, and 1.7-fold on growth on acetate, fructose, and citrate, respectively.

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Arthrobacter globiformis S14-3 produced a novel type of inulin decomposing enzyme in the culture broth. The enzyme converted inulin into di-D-fructofuranose-l, 2';2, 1'-dianhydride (DFA I) and a small amount of oligosaccharides. The enzyme was purified 63-fold by DEAE-Toyopearl chromatographies. The optimal pH for the enzyme reaction was 6.0, and the optimal temperature was 40°C. The enzyme was stable up to 70°C in 8 HIM phosphate buffer, pH 6.0. Hg²⁺ and Fe³⁺ (1 MM) strongly inhibited the enzyme activity. By SDS-PAGE, the molecular weight of the enzyme was estimated to be 39, 000.
The NH₂-terminal amino acid sequence of the enzyme was determined to be
H₂N-Ala¹-Asn²Thr³-Val⁴-Tyr⁵-Asp⁶-Val⁷-Thr⁸-Thr⁹-Trp¹⁰-Ser¹¹-Gly¹²-Ala¹³-Thr¹⁴-Ile¹⁵-Ser¹⁶-Pro¹⁷-Tyr¹⁸-Val¹⁹-Asp²⁰.

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(-)-Biopterin was synthesized from (1S, 2S)-1-(l, 3-dithian-2-yl) propane- 1, 2-diol 5 (= C), which was derived from commercially available (S)-ethyl lactate. Diol 5 (= C) was converted to 15 through a six-step sequence. Ketone 15 was submitted to condensation with 3, 5, 6-triaminopyrimidinol (TAP, 2), and followed by oxidation to afford isopropylidenebiopterin (16). Finally, 16 was deprotected to give (-)-biopterin (1).

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D-Glyceric acid is a useful chiral synthon in synthetic organic chemistry. To produce D-glycerate cheaply, microorganisms that convert L-tartrate into D-glycerate with good yields and selectivity were isolated from soil samples. One microorganism obtained was identified as a strain of Pseudomonas sp. group Ve-2 and found to produce a new enzyme, L-tartrate decarboxylase. This enzyme catalyzes the direct conversion of L-tartrate into D-glycerate, with almost 100% selectivity. In the presence of a cell-extract of Pseudomonas sp. group Ve-2, the amount of D-glycerate produced from L-tartrate reached 53g/l under the best conditions examined, with a molar yield of almost 100% and an optical purity of more than 92% e.e.

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The possible roles of caseins as exorphins, immunostimulants and hypotensive agents have recently been suggested by several groups. In an attempt to prove the existence and to elucidate the physiological significance of peptide inhibitors of angiotensin-converting enzyme (ACE) in milk proteins, we synthesized a total of 69 peptide fragments of human β-casein, in which a proline residue was placed at the C-terminus for the ACE inhibitory activity. It was found that the peptides with potent inhibitory activity in vitro were located in the region of amino acid residues 39 - 52 of human β-casein. All the peptides within this sequence (39-52) had potent ACE inhibitory activity. The most potent inhibitor was a decapeptide, Ser-Phe-Gln-Pro-Gln-Pro-Leu-Ile-Tyr-Pro (IC₅₀=1.4 μM), which was also active in vivo.

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The cultural conditions for obtaining a high concentration of Eschenchia coli K12 cells were investigated. A synthetic medium containing high concentrations of mineral salts was designed so as to support a high rate of cellular growth and the accumulation of a high cell concentration, without any additional feeding of inorganic nutrients, but with feeding of solid glucose.
The pasteurization of the above mentioned medium at 65°C was found to be advantageous for the cellular growth since usual sterilization at 121°C caused denaturation of the medium, which was inhibitory for cellular growth.
The accumulation of acetate, a well-known inhibitory product for the growth of E. coli, increased as the dissolved oxygen (DO) concentration decreased. When the DO concentration was maintained at the optimum value of 6.5ppm throughout the cultivation by pressurizing the culture system with oxygen gas, 134 g (dry basis)/l of cells was accumulated in 12 hr.
The above culture conditions were applied to the cultivation of a recombinant E. coli strain transformed with pBR322trpAB, and 102g/1 of recombinant cells was obtained with a stably maintained recombinant plasmid in 9 hr under nonselective pressure.

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Bacillus thuringiensis var. israelensis produces 130-kDa proteins which are toxic to mosquito larvae. The ISRH4 gene encoding 1, 180 a mi no acids of the 130-kDa insecticidal protein was fused with lacZ' on a plasmid, pUC19, and sequentially deleted from the C-terminus to construct a series of deletion mutants. All the deletion mutant genes directed the production of truncated ISRH4 proteins fused with the α-complementing fragment of β-galactosidase in Escherichia coli cells in the presence of isopropyl β-D-thiogaIactopyranoside. Analysis of the mosquito larvicidal activity of deletion mutant proteins revealed that the N-terminal 29 amino acids and the C-terminal 485 amino acids could be removed without loss of the activity.

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The substrate specificity of α-D-xylosidase from Bacillus sp. No. 693-1 was further investigated. The enzyme hydrolyzed α-1, 2-, α-1, 3-, and α-1, 4-xylobioses. It also acted on some heterooligosaccharides such as O-α-D-xylopyranosyl-(1→6)-D-glucopyranose, O-α-D-xylopyranosyl-(1→6)-O-β-D-glucopyranosyl-(1→4)-D-glucopyranose, O-α-D-xylopyranosyl-(1→6)-O-β-D-glucopyranosyl-(1→4)-O-[α-D-xylopyranosyl-(1→6)]-D-glucopyranose, and O-α-D-xylopyranosyl-(1→3)-L-arabinopyranose. The enzyme was unable to hydrolyze tamarinde polysaccharides although it could hydrolyze low molecular weight substrates with similar linkages.

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The biosynthetic route for chloromonilicin, an antifungal substance from cherry rot fungus, was investigated using deuterium-labeled precursors. The incorporation of synthetic deuterium-labeled moniliphenone into chloromonilicin and into its xanthone precursor, 4-chIoropinselin, was confirmed by ¹H-NMR spectrometry.

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A remarkable improvement in the emulsifying properties of proteins was observed in mixtures of serum albumin-dextran sulfate, lysozyme-dextran sulfate, serum albumin-chondroitin sulfate, α-lactalbumin-chondroitin sulfate and lysozyme-chondroitin sulfate. The emulsifying properties of these protein-polysaccharide complexes were affected by the molecular size of the polysaccharide and by such conditions as the presence of salt, acidic or alkaline pH, and heating. On the other hand, the emulsifying properties of ovalbumin-dextran hybrids prepared by covalent attachment were more enhanced in alkaline pH or by heating. The molecular size of the ovalbumin-dextran hybrids greatly affected the emulsifying properties.

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Not only Cytochrome P-450 but also cytochrome b₅-like hemeproteins, NADPH-cytochrome c reductase, and NADH-ferricyanide reductase activities could be detected in the cell-free extract of a cytochrome P-450-producing fungus, Fusarium oxyspornm. Both cytochromes (P-450 and b₅) could be reduced anaerobically with a natural reductant (NADPH or NADH), suggesting the existence of an electron transport system to reduce the cytochromes. Further, two monooxygenase activities, _i.e., N-demethylase and benzo[a]pyrene monooxygenase, were also found in the extract in addition to the fatty acid hydroxylase previously found. These components and activities seemed to be induced concomitantly. One of the cytochrome b₅-like hemeproteins was isolated, the absorption spectra and molecular weight (M_r = 16, 200) of which closely resembled those of hepatic cytochrome b₅ of mammals. From these results we concluded that this fungus has a cytochrome P-450-containing electron transport system similar to that in hepatic microsomes of mammals in addition to the unique nitrate/nitrite-inducible cytochrome P-450 system previously found.

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Streptococcus dysgalactiae IID 678, belonging to group C of the streptococci, secreted a large amount of hyaluronidase (hyaluronate lyase, EC 4.2.2.1) into a culture medium containing hyaluronic acid. The purification procedures of hyaluronidase were 70% ammonium sulfate precipitation, ECT EC) LA-eel hi lose chromatography, phospho-cellulose chromatography, and gel filtration on Sephacryl S-300. The hyaluronidase was purified approximately 27, 000-fold from the culture filtrate. The purified enzyme was homogeneous by SDS-polyacrylamide gel electrophoresis. The enzyme degradated only hyaluronic acid and chondroitin to Δ4, 5-unsaturated disaccharides and did not act on other glycosaminoglycans containing sulfate groups, while the degradation rate of chondroitin was about 1/60 of that of hyaluronic acid. The optimum pH was wide, from pH 5.8 to pH 6.6, and the optimum temperature was 37°C. Fe²⁺, Cu²⁺, Pb²⁺, and Hg²⁺ ions inhibited the activity strongly and Zn²⁺ inhibited it by half. The molecular weight of the enzyme was estimated to be 125, 000 by gel filtration and 117, 000 by SDS-polyacrylamide gel electrophoresis. The enzyme was different immunochemically from the hyaluronidase from Streptococcus pyogenes belonging to group A.

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An efficient method for the isolation of dihydrodipicolinate synthase (DPS)-defective threonine producers from a Brevibacterium strain with feedback-sensitive aspartokinase (AK, AK^S) was established. After mutagenesis of a strain with AK^S, No. 70, mutants resistant to α-amino-β-hydroxyvaleric acid were isolated and then selected as to threonine productivity in the presence of diaminopimelic acid. DPS activity in the strains in which the threonine production was inhibited by lysine was found to be absent or reduced to less than 10% of the level in the parent. On the other hand, the strains in which the production was not inhibited by lysine were conventional threonine producers with feedback-resistant homoserine dehydrogenases (HDs and HD^Rs) and wild type DPS. The HD activities of most of the threonine mutants were also markedly reduced. However, only one mutant lacking DPS, DK330, exhibited an HD level comparable to that in the parent and produced the largest amount of threonine among the threonine producers obtained. The formation of HD and HK in strain DK330 was hardly repressed by the addition of methionine. Under the optimum conditions, strain DK330 produced 12.4 of threonne, while a typical HD^R type threonine producer, BK29, produced 9.9g/l.

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From the pollen of sunflower (Helianthus annuus L.), the biologically active substances in the rice lamina inclination test were extracted and partially purified. They were converted to bis-9-phenanthreneboronates and bismethaneboronates, and analyzed by fluorescence HPLC and GC/MS analytical methods, respectively. The active principles were identified as brassinolide, castasterone and norcastasterone (brassinone).

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Maltosyl(α1→6)α-, β- or γ-cyclodextrin was synthesized from maltose and α-, β- or γ-cyclodextrin, respectively, using Bacillus acidopullulyticus pullulanase (EC 3.2.1.41). More than 40% of each cyclodextrin substrate was converted to the corresponding maltosyl(α1→6)cyclodextrin under the conditions given below; the combined concentration of maltose and cyclodextrin was 70-75% (w/w), the molar ratio of maltose to cyclodextrin was 9-18, and the amount of pullulanase was 100-200units/g of cyclodextrin. The optimum pH and temperature for the formation of maltosyl(α1→6)cyclodextrins were 4.0-4.5 and 60-70°C, respectively. Each maltosyl(α1→6)cyclodextrin produced was separated from noncyclic saccharides, maltose and branched tetraose, by methanol and ethanol precipitations. The maltosyl(α1→6)cyclodextrins were further purified by gel filtration on a Toyopearl HW 40 S column and crystallization from aqueous (for maltosyl(α1→6)α- cyclodextrin) or methanol (for maltosyl(α1→6)β-cyclodextrin) solution. From 10g each of the corresponding cyclodextrin, the yields of the purified maltosyl(α1→6)α-, β- and γ-cylcodextrins were 3.0-3.6g, 2.5-2.8g and 2.2-2.5g, respectively. Identification of the maltosyl(α1→6)cyclodextrins was performed by means of hydrolysis with Klebsiella pneumoniae pullulanase, methylation analysis and ¹³C-NMR analysis.

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The hydrolytic products of a chitinase purified from Nocardia orientalis were examined on reduced (GlcNAc)_n(n = 2-6). The rate of hydrolysis on reduced (GlcNAc)_4-6 increased with increasing chain-length of N-acetylglucosamine residues, but the enzyme did not act on reduced (GlcNAc)₂ or reduced (GlcNAc)₃. Based on the analysis of the frequency distribution of bond cleavage on PNP-(GlcNAc)_n(n = 2-5) in the initial hydrolysis, the enzyme was shown to release predominantly (GlcNAc)₂ from the nonreducing end of each substrate. The enzyme, which is essentially a hydrolase, also catalyzed a transglycosylation reaction in an excess of (GlcNAc)₄ as an initial substrate. In this case, the addition of ammonium sulfate to the reaction system resulted in a significant increase in (GlcNAc)₆ production. The yield of the hexasaccharide was about 34% of the chitinase-catalyzed net decrease of (GlcN Ac)₄. The rate of the transglycosylation in the presence of ammonium sulfate greatly depended on the salt concentration, the temperature, and the substrate concentration.

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Nucleoside oxidase that was purified to an electrophretically homogeneous state catalyzed the oxidation of hydroquinone only in the presence of nucleosides simultaneously with the oxidation of nucleosides. From the identification of the reaction products and a chemical balance study, we concluded that the oxidation of hydroquinone proceeded by the following scheme: 2 hydroquinone + O₂→2p-quinone + 2H₂O. The enzyme also catalyzed the oxidation of various phenolic compounds and strongly colored substances were formed from phenolic compounds with 4-aminoantipyrine in proportion to the amount of nucleosides.

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A thermostable purine nucleoside phosphorylase has been purified more than 800-fold from Bacillus stearothermophilus JTS 859. The enzyme had a molecular weight of 68, 000 consisting of 2 identical subunits (M_w, 34, 000). The isoelectric point of the enzyme was 4.7. The enzyme did not contain cysteine. The optimal pH of the enzyme reaction was from 7.5 to 11.0. The Michaelis constants for inosine, guanosine, 2'-deoxyinosine, and 2'-deoxyguanosine were 0.22, 0.14, 0.20, and 0.10 HIM, respectively. The optimal temperature of the reaction was 80°C. The half-life of the enzyme was 16 hr in 20 mM potassium phosphate and 1 mM inosine (pH 7.0) at 80°C, and no decrease of the enzyme activity was observed at least for the first 30 hr at 70°C.

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Water-soluble carbodiimide [EDC: (l-ethyl-3-(3-dimethylaminopropyl)carbodiimide)] is a useful reagent for chemical modification of carboxyl group of various proteins. Model experiments to establish detailed conditions for the cross-linking reaction with EDC were conducted. Since the reactivity of hexamethylenediamine as a nucleophile was almost comparable to that of glycine ethyl ester, AH-Sephadex and the carboxyl group of aspartylphenylalanine methyl ester were coupled by EDC. From the hydrolyzate of the isolated gel, aspartic acid and phenylalanine methyl ester were identified. When bovine serum albumin (BSA) was incubated with AH-Sephadex and EDC, about 90 % of the BSA was coupled to the gel by 3hr incubation. Moreover, BSA was effectively coupled with the carboxymethyl cellulose (CMC) after activation of the carboxyl groups of CMC with EDC followed by the removal of excess EDC. The latter case would be useful for cross-linking the enzyme molecules to the matrix because of the very mild reaction conditions. For example, endodextranase, which readily lost its activity upon being incubated with EDC (suggesting that a carboxyl group was essential for the enzyme activity), was effectively immobilized to CMC with EDC. This improved reaction step for the cross-linking seemed to be especially useful for the glycosylases, because in most of these enzymes carboxyl groups play a role in the catalytic residue.

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When the cells of an n-alkane-assimilating yeast, Candida maltosa I AM 12247, were transferred from a glucose medium to an n-alkane medium, various enzymes are induced in the endoplasmic reticulum and peroxisome. Cytochrome P-450alk, one of these enzymes in the endoplasmic reticulum, was purified after mild solubilization of the membrane, followed by a few steps of chromatography. The enzyme was characterized spectrophotometrically and its N-terminal amino acid sequence (12 residues) was determined.
Using oligonucleotide probes prepared to match parts of the N-terminal amino acid sequence and 4 of the partial cDNA sequence of Cytochrome P-450alk of C. maltosa EH 15, we isolated from a gene library of C. maltosa I AM 12247 a clone which had a gene encoding Cytochrome P-450alk. By nucleotide sequencing of this gene, the amino acid sequence of this enzyme was deduced. It consisted of 523 amino acids (59, 838 daltons), with a non-cleavable signal sequence in the N-terminal region. The structure of this enzyme was compared with some other members of the cytochrome P-450 superfamily.

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Chemical modification of tryptophan residues in ricin E was investigated with regard to saccharide-binding. Two out of ten tryptophan residues in ricin E were modified with N-bromosuccinimide at pH 4.5 in the absence of specific saccharide accompanied by a marked decrease in the cytoagglutinating activity. Such a loss of the cytoagglutinating activity was found to be principally due to the oxidation of one tryptophan residue per B-chain. In the presence of lactose, one tryptophan residue/mol was protected from the modification with retention of a fairly high cytoagglutinating activity. However, GalNAc did not show such a protective effect. The binding of lactose to ricin E altered the environment of the tryptophan residue at the low affinity binding site of ricin E, leading to a blue shift of the fluorescence spectrum and an I V -difference spectrum with a maximum at 290 nm and a trough at 300 nm. The ability to generate such spectroscopic changes induced by lactose was retained in the derivative in which one tryptophan residue/mol was oxidized in the presence of lactose, but not in the derivative in which two tryptophan residues/mol were oxidized in the absence of lactose. Based on these results, it is suggested that one of the two surface-localized tryptophan residues is responsible for saccharide binding at the low affinity binding site of ricin E, which can bind lactose but lacks the ability to bind GalNAc.

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Lignin-carbohydrate complexes (LCC; nor-C-1-M, com-C-1-A) isolated from normal and compression woods of Pinus densiflora were hydrolyzed with two types of cellulase preparations, and the hydrolyzates formed were fractionated by adsorption chromatography on polyvinyl gel into water-soluble materials and LCC fragments. To elucidate the binding sites between the lignin and carbohydrate, the cellulase-degraded LCC fragments were subjected to acetylation, and then oxidation with 2, 3-dichloro-5, 6-dicyano-l, 4-benzoquinone (DDQ), which was confirmed to oxidatively cleave the benzyl ether linkages between the lignin and carbohydrate. The DDQ-oxidized fraction was then methylated by the method of Prehm, hydrolyzed, reduced and acetylated. A GC-MS analysis of the methylated sugar revealed that alditol acetates from 6-O-methyl mannose, 6-O-methyl galactose, 6-O-methyl glucose and a small amount of their 2-O- or 3-O-methyl isomers existed in both methylated fractions. 2-O-Methyl xylose and 3-O-methyl xylose were also identified in the fraction from the acidic LCC (com-C-1-A). These results led to the conclusion that acetylglucomannan and β-1, 4-galactan were preferably bound to the lignin at C-6 position of the hexoses, and that arabinoglucuronoxylan did likewise at the C-2 and C-3 positions of xylose units.

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The synthesis of (-)-cis-neocnidilide (1), a stereoisomer of neocnidilide (2) having inhibiting activity against mycotoxin-producing fungi, is described. (±)-(E)-1, 3-Nonadien-5-ol was kinctically resolved to give (S)-13, which was converted to (S)-triene ester 8. The intramolecular Diels-Alder reaction of 8 afforded a mixture of 12 and 10. The dihydro derivative 14, obtained by catalytic hydrogenation of 12, was transformed via trimethylsilylketene acetal into α-bromolactone 19, which upon treatment with DBU in toluene, gave rise to (-)-cis-neocnidilide (1).

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The tumor promoter, indolactam-V (1a), was synthesized in 8 steps and a 15% overall yield from methyl 4-nitroindole-3-carboxylate (2). Several chemical properties of indolactam-V analogs 10a and 10b were investigated.

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