In the present study, the following novel pyridoxal enzymes have been demonstrated, purified to homogeneity, and characterized enzymologically and physicochemically: lysine ε-transaminase, taurine transaminase, ε-amino acid transaminase, amino acid racemase with low substrate specificity, arginine racemase and selenocysteine β-lyase from bacteria, and the last also from mammalian tissues. Other known but unpurified pyridoxal enzymes were purified mainly from micro-organisms and characterized: kynurenine transaminase, D-amino acid transaminase, ornithine δ-transaminase, γ-aminobutyrate transaminase, aspartate transaminase, alanine racemase, α-amino-ε-caprolactam racemase, aspartate β-decarboxylase, lysine decarboxylase, ornithine decarboxylase, methionine decarboxylase, meso-α, ε-diaminopimelate decarboxylase, kynureninase, methionine γ-lyase, glucosaminate dehydratase and several others. Selenocysteine β-lyase, a novel enzyme that exclusively decomposes L-selenocysteine into L-alanine and elemental selenium was found in various mammalian tissues and aerobic bacteria. The enzyme was purified to homogeneity from pig liver and its physicochemical and enzymological properties were studied. The enzyme is the first proven enzyme that specifically acts on selenium compounds. meso-Diaminopimelate decarboxylase, a pyridoxal 5'-phosphate enzyme that catalyzes the decarboxylation of the R_D center of meso-diaminopimelic acid to give L-lysine, has been purified to homogeneity from Bacillus sphaericus. The enzyme was found to operate with inversion of configuration, in direct contrast to other PLP-dependent α-decarboxylases for which the stereochemistry of reaction has been determined. In all other cases examined, the reaction proceeds with retention of configuration--that is, the incoming proton occupies the same stereochemical position as did the departing carboxyl group. We have purified and crystallized four bacterial ε-aminotransferases: L-lysine ε-aminotransferase, taurine: α-ketoglutarate aminotransferase, ε-amino acid: pyruvate aminotransferase, and L-ornithine δ-aminotransferase, to characterize them. L-lysine ε-aminotransferase and L-ornithine δ-aminotransferase are unique among aminotransferases: they are specific for L-amino acids but act on the distal amino group to the prochiral carbon atom. The products, L-α-aminoadipic δ-semialdehyde and L-glutamic γ-semialdehyde, in both enzyme reactions are spontaneously converted into the intramolecularly dehydrated form. Δ^1-piperideine-6-carboxylate and Δ^1-pyrroline-5-carboxylate, respectively; the reactions are virtually irreversible. In order to obtain information on the orientation of substrates in the active sites of these enzymes, the stereochemistry of the proton abstraction by L-lysine ε-aminotransferase and L-ornithine δ-aminotransferase has been investigated. Both the ε-aminotransferases have been shown to abstract stereospecifically the pro-S hydrogen atom from the ε-amino group bearing carbon atoms of their amino donors.

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Folate content in various commercial dried seaweeds were determined by a microbiological assay method, in order to evaluate the availability of seaweeds as a source of folate. An improved technique by pretreatment with cellulase was employed for preparation of sample solutions from seaweeds. Total folate contents in several dried seaweeds estimated by the improved method were about 2 times of those obtained by the usual method, and varied from 140.5 (Konbu) to 717.5 (Amanori) μg/100g dry weight. About 38% of total folate contents in Arame exuded into water during 30-min immersion, while the rate was 21.7% for Konbu, and the folates extracted were almost of their free forms.

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This paper deals with the decomposition of thiamin in blood samples under various storage conditions. Human whole blood, blood cells, plasma and deproteinized solutions of blood samples were stored under various conditions. Thiamin concentration was determined after 2 or 4-week storage. Thiamin concentration in whole blood or blood cells was decreased markedly at pH 6.0, 4.0℃ but not at -4℃ after 2 or 4 week storage. Thiamin in plasma was not decomposed under any conditions. Thiamin in a deproteinized solution was decreased slowly at pH 6.0, 4℃. The thiamin-decomposing factor(s) in blood was adsorbed by a cation exchange resin (Amberlite XE 100) but not by an anion exchange resin (Amberlite IRA 410).

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Alpha-tocopheryl acetate of 50 mg/kg/day was orally administered every day to low birth weight infants 7 days after birth, and changes in plasma and RBC tocopherol levels were examined. 1. An increase in plasma and RBC tocopherol levels was observed during the first 2 to 3 weeks of the administration which was followed by a slightly decrease thereafter. Changes in plasma tocopherol/total lipid ratio showed a similar pat-tern to those in plasma and RBC tocopehrol levels. 2. During the late periods of examination (more than 2 weeks), plasma tocopherol and tocopherol/total lipid ratio were kept at the levels corresponding to adult values, or higher levels. 3. A close correlation between plasma tocopherol and RBC tocopherol levels was observed all through the periods of administration. 4. A close correlation between plasma tocopherol and plasma total lipids or betalipoproteins was also observed either in the early periods or late periods of the administration. However, the increasement of plasma tocopherol against that of plasma lipids was much larger in the late periods than in the early periods.

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