1. The influence of unsaturated fatty acids on the mono-unsaturation of stearic acid in vitro was investigated.
2. Poly-unsaturated fatty acids, such as linoleic and arachidonic acids remarkably depressed the desaturation of stearic acid-l-¹⁴C. Oleic acid was also inhibitory, but less so than poly-unsaturated acids. This inhibition is not due to lipid hydroperoxide formation.
3. The removal of free fatty acid from the soluble fraction of the enzyme preparation caused a significant elevation of desaturating activity.
4. Fatty acid desaturation is partially regulated by the amount of unsaturated fatty acid.

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1. 2-Methoxy-5-nitrotropone, a new reagent for reversible chemical modification of amino groups in protein, was studied with Taka-amylase A [EC 3. 2. 1. 1] as the sample protein.
2. Treatment of Taka-amylase A with 2-methoxy-5-nitrotropone results in about 65% loss of the amylase activity and some activation of the maltosidase activity. Nitrotroponyl Taka-amylase A can be denitrotroponylated by hydrazine. The regenerated Taka-amylase A is not distinguishable from intact Taka-amylase A by DEAE-cellulose column chromatopraphy, enzyme activities, optical rotatory dispersion or susceptibility to bacterial proteinase.
3. The ε-amino groups of lysine residues in Taka-amylase A may not be essential for the amylase activity and the decrease of the amylase activity of nitrotroponyl Taka-amylase A may be due to a steric hindrance by the nitrotroponyl residue combined with the amino group of a lysine residue situated close to the active site.

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The subcellular particles of guinea-pig brain were incubated with [γ-³²P] ATP in the presence of potassium chloride (100mM), magnesium sulfate (3mM) and Tris-HCl buffer (pH 7.4). Labeling of phospholipids was followed by the column method after deacylation. The results are summerized as follows: 1) Labeling of triphosphoinositide, diphosphoinositide and phosphatidic acid with ³²P was observed after a few second incubation at 0°C. In various periods of incubation up to a few minutes the percentage of ³²P-activity in polyphosphoinositides increased, whereas no increase was observed in phosphatidic acid. 2) The in corporation of ³²P-phosphate into phosphoinositides was markedly depressed by the addition of calcium ion in a final concentration of 3mM. 3) Sodium ion exerted no specific effect on the labeling of the phospholipids from [γ-³²P] ATP.

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Nonspecific adenosine deaminase [EC 3. 5. 4. 4] from Takadiastase catalyzed dechlorination of 6-chloropurine riboside, yielding inosine and chloride ion as reaction products. The Michaelis constant for 6-chloropurine riboside was 0.65×10^-3M. The V value for the dechloronase activity was only one-seventieth of that for deamination of 5'-AMP. The dechloronase activity was competitively inhibited by adenine and 6-chloropurine. The spectra of mixtures of enzyme and 6-chloropurine or adenine were not the sum of the spectra of two constituents. Several enzyme preparations had the same ratio of deaminase activity to dechloronase activity. These data suggest that a single enzyme is involved in both the deamination and the dechlorination reaction.

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1. pH Dependence of RNA degrading activity of brain homogenate revealed a peak near pH 6.
2. Starting from acetone powder of beef brain, the activity at pH 6 was purified by extraction with 0.15M sodium chloride, ammonium sulfate fractionation, pH4 treatment, acetone treatment, and DEAEcellulose column chromatography. Further purification by zone electrophoresis was also performed when desirable.
3. The purified enzyme had a pH optimum at 6.2, required no metal ions, and was relatively unstable to heat and acid treatments.
4. The purified enzyme hydrolyzed RNA completely to acid-soluble material. The products were 3'-adenylic acid, 3'-guanylic acid, and pyrimidine nucleotides, probably bearing their phosphate group in the 3' position.
5. Thymidyly1-3': 5'-thymidine was hydrolyzed by the enzyme and formed 3'-thymidylic acid and thymidine. 3'-Thymidylic acid was identified enzymatically by venom 5'-nucleotidase EEC 3. 1. 3. 51. Denatured DNA, ribonucleoside-2', 3' cyclic phosphates, and di (p-nitrophenyl) phosphate were not attacked.

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In the presence of sodium dodecylsulfate or guanidine hydrochloride, the following results were obtained.
(1) All of the intrinsic copper atoms in cytochrome α were removed by dialysis against cyanide solution.
(2) The addition of PCMB to a cytochrome α preparation caused liberation of copper and at the same time the oxidase [EC 1. 9. 3. 1] activity was extremely inhibited by PCMB.
(3) Since there is a correlation between the titration of the seventh sulfhydryl group and copper liberation, it is possible that the intrinsic copper in cytochrome α is primarily linked to the sulfur atom of the last titratable sulfhydryl group. The other six sulfhydryl groups do not seem to be necessary for the oxidase activity.

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Spectrophotometric titration of the tyrosyl groups of three type K and three type L Bence Jones proteins was performed by measurements both at 246 and 296mμ at 25°C. It was found that tyrosyl ionization of all the Bence Jones proteins studied here is abnormal. In the presence of 3M guanidine hydrochloride (GuCl), however, the titration curves became normal. From the titration curves at 296mμ in the presence of 3M GuCl, it was found that three type K proteins contain eighteen tyrosyl residues and two of three type L proteins contain twelve and the other type L protein contains seventeen tyrosyl residues per molecule of molecular weight of 43, 000.
The molecular weight of a type L Bence Jones protein was determined by the Archibald method and was found to be 43, 000.
The difference spectra of type K and L Bence Jones proteins produced by 6M urea were measured. It was found that antigenically different Bence Jones proteins give a different ratio of the absorbancy change at a peak near 293mμ to that near 285mμ in the difference spectra.

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Latex of the Japanese lacquer tree was found to contain a phenolase [EC 1.10.3.1] and a peroxidase [EC 1. 11. 1.7] in addition to laccase [EC 1.10.3.2], and the three enzymes were separated from one another. Laccase was purified to a homogeneous state and shown to be incapable of catalyzing the aerobic oxidation of coniferyl alcohol. The phenolase separated from the latex could oxidize coniferyl alcohol, though it contained little contaminating peroxidase. The peroxidase obtained from the latex, like wheat germ peroxidase 556, could catalyze active oxidation of coniferyl alcohol in the presence of hydrogen peroxide; the activity could be detected even with low concentrations of hydrogen peroxide and coniferyl alcohol. The formation of a lignin-like dehydrogenative polymerization product from coniferyl alcohol by the action of phenolase and peroxidase could be detected by measuring increases in turbidity and also by changes in absorption spectrum of the reaction mixtures. The formation of the polymerization product was much faster with peroxidase than with phenolase. It was concluded that the oxidation of coniferyl alcohol by the crude latex extract was due to the action of phenolase but not to that of laccase.

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1. A new bile alcohol, 5α-cholestane-3α, 7α, 12α, 25, 26-pentol (5α-bufol) was synthesized from 5α-cholestane-3α, 7α, 12α, 26-tetrol.
2. It was verified by column, paper, thin layer and gas chromatographic analyses that the bile of the newt contains 5α-bufol, 5α-cyprinol and cholestanehexols.

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1. In order to effectively examine the distribution of ceramide 2-aminoethylphosphonate and ceramide aminoethylphosphate (sphingoethanolamine) in some aquatic animals, their alkali-stable lipid fractions were prepared, and they were analyzed by thin-layer chromatography and an amino acid analyzer. Such two methods of analysis are described.
2. Results obtained by these two methods indicated that all the members of bivalves, snails and cephalopods examined contain either one or two ceramide derivatives. However, neither of the ceramides could be found in the two species of fishes examined.

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1. A seasonal change was observed in the total level of pyruvate kinase [EC 2.7. 1.40] in rats fed on laboratory chow or a high carbohydrate diet.
2. Two types of pyruvate kinase were identified by electrophoresis and an immunological procedure, and named type L and type M. Both types were purified extensively and were isolated as crystals. The molecular weights of type M and type L were 250, 000 and 208, 300 respectively.
3. No cross immunological reaction was observed between the two types. The antibody for type M was used in estimating the levels of the two types of enzyme in tissue extracts.
4. The level of type L varied greatly under various physiological conditions, whereas that of type M changed only slightly. In alloxan diabetic animals and those fed on a high protein diet or fasted for 48 hours, the total level of pyruvate kinase as well as the ratio of type L to type M decreased greatly, and on subsequent insulin administration and administration of a normal diet, respectively, the level returned to normal.
5. The level of type M increased markedly in regenerating liver and was the only type found in ascites hepatoma cells.
6. Type M was present in muscle, brain, heart, liver, kidney, fat pads and leucocytes, and type L was only present in liver and erythrocytes.
7. The kinetic properties of type M and type₁ were quite different. The apparent K_m of type L₁ for phosphoenolpyruvic acid was about 10 times that of type M, and with type L, the substrate seemed to act as an activator. The sensitivities of type ₁ to inhibition by ATP and p-chloromercuribenzoic acid were also very much higher than that of type M.
8. The physiological significances of the two types of pyruvate kinase were discussed.

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1. For the study of the specificity of purine derivatives to the repression of five enzymes involved in the purine nucleotide biosynthetic pathway, several mutant strains, which did not convert the test purine derivatives to the other type of purines, were derived from purine requiring mutants of B. subtilis Marburg.
2. IMP dehydrogenase [EC 1. 2. 1. 14], an enzyme involved in the formation of GMP, was repressed only by guanosine and not repressed by adenosine, xanthosine and inosine.
3. Adenylosuccinate synthetase [EC 6. 3. 4. 4], an enzyme forming AMP, was repressed only by adenosine but neither by guanosine, inosine, nor xanthosine.
4. IMP transformylase and phosphoribosyl pyrophosphate amidotransferase [EC 2. 4. 2. 14], the enzymes forming IMP, a common precursor of both AMP and GMP, were repressed by adenosine or guanosine, slightly by inosine but not by xanthosine.
5. Adenylosuccinate lyase [EC 4. 3. 2. 2], an enzyme forming IMP as well as forming AMP, was repressed by adenosine or guanosine, slightly by inosine but not by xanthosine.
Based on these results, the repression in purine nucleotide biosynthesis was discussed to be rational as the regulator control mechanism.

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Spectrophotometric titration of the tyrosyl groups of bovine heart, Saccharomyces oviformis, and Candida krusei ferricytochromes c was carried out by measuring the optical densities at 244mμ at various pH's. It was found that tyrosyl ionization of the three species of cytochromes c studied here is abnormal. From the optical rotatory dispersion studies, it was found that the conformation of the cytochrome c molecule is disrupted above pH 11.5 However, even the tyrosyl residues which ionize below pH 11.5 have abnormally high pK values. The titration curves of the tyrosyl residues of the three species of cytochromes c are different from each other. This suggests that the difference in the amino acid sequence in the linear structure may affect the ionization of the tyrosyl residues located at the same positions. The titration curve of Candida krusei ferrocytochrome c was located in a higher pH range than that of ferricytochrome c and about four of the five tyrosyl residues were titrared below pH 12.

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The isolation and the structure of glycolipids from Nakahara- Fukuoka sarcoma tissue is described. Glycolipids were purified by column chromatography on silicic acid, on Florisil and by crystallization with methanol. Four types of sphingolipid, ceramides, CMH, CDH and CTH were isolated in a pure state. In contrast to BP3/C3H mouse ascites sarcoma cells, N. F. sarcoma tissues contained nearly equimolar amounts of each glycolipid with a trace of globosides. The glycolipids were cleaved by various methods and the components were determined by G. L. C. mainly. CMH consisted of about 86% glucocerebrosides and about 14% galactocerebrosides. CDH was mainly lactosyl ceramide. CTH was mainly galactosyl (α1→4) galactosyl (β1→4) glucosyl (1→1') ceramide. The long chain bases present were 18-dihydrosphingosine and 18-sphingosine in the ratio of about 4:6 and the pattern of fatty acid was similar to that of sphingomeyelin (1).

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As a part of the project for studying the substrate specificity of egg white lysozyme [EC 3.2.1.17], mucopolysaccharide backbone of cell walls isolated from Micrococcus lysodeikticus was modified and the enzymatic action on the modified substrates was examined in comparison with the intact cell walls, together with chitin derivatives. In order to prepare the modified substrates, cell walls or whole cells were refluxed with hydrazine hydrate for 24 hours, and the soluble and nondialyzable material thus obtained, in which a considerable part of the acetyl residues and all the amino-acids except for a small amount of alanine had been removed, was N-reacetylated on the one hand, and N-propionylated on the other. The hydrazine-treated material, which contained muramic acid and glucosamine, revealed scarce susceptibility to the enzyme, while the N-reacetylated product of it was a soluble and good substrate of lysozyme. The N-propionylation of the hydrazine-treated cell walls did not restore the susceptibility. These facts suggest that the size of the N-acyl substituent in the amino groups of glucosamine residues in the polysaccharide chain is a determining factor for the susceptibility to lysozyme.
The experiments carried on the glycolated chitin resulted in an analogous conclusion. “Glycol chitin”, which had been known as a soluble substrate of the lysozyme, was likewise treated with hydrazine. Diminution of the N-acetyl residues decreased the susceptibility of the material to the lysozyme action. N-Reacetylation restored an additional activity, while N-propionylation did not.

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