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11S globulin, the major storage protein of soybean seeds, was isolated to be homogeneous in ultracentrifugation, disc electrophoresis and isoelectric focusing by a comparatively simple method using gel filtration on Sephadex G-100 and G-200 columns with a good yield. The protein had the molecular weights of 309,000–322,000 by three separate methods based on different principles. Subsequently, some physico-chemical properties of the protein were determined. For example, sedimentation coefficient, isoelectric point, intrinsic viscosity and absorptivity constant were 12.2S, pH 4.64, 0.0485 dl/g and 8.04, respectively. Optical rotatory dispersion studies of the protein gave the values of a0 = —246 and b0 = —33. The contents of α-helix and β structure calculated from these parameters were estimated to be 5.2% and 34.8%, respectively.

The molecular shape of the 11S globulin, the major storage protein of soybean seeds, was estimated to be an oblate ellipsoid with a revolution axial ratio of 8.11-8.38 with or without scarce hydration according to the procedure of Simha & Perrin by measuring the partial specific volume, diffusion coefficient, molecular weight and volume fraction intrinsic viscosity. The length of the major axis of the molecule is 178-180 A and that of the minor axis 22 A. Subsequently, the shape factor beta, and the hydrodynamically effective volume, Ve, of the protein were calculated by the procedure of Scheraga & Mandelkern. Consequently, the 11S globulin molecule was also an oblate ellipsoid from beta. Ve was found to be equal to MV/N, the anhydrous volume of protein. It was therefore concluded that the protein existed in a rigid and nearly anhydrous state in solution.

Two kinds of dimeric procyanidins were isolated in pure form from azuki beans by preparative HPLC. They were identified as procyanidins B-1 and B-3, on the basis of their UV, IR FAB-MS and 1H-NMR spectra, and an analysis of the acid hydrolyzed products. The procyanidins were evaluated as antioxidants for linoleic acid in an aqueous linoleic acid-β-carotene model system. In the range of the tested concentrations (5 × 10−5~100 × 10−5%) and pH values (7~9), they showed remarkable antioxidative activities. Their activities were much stronger than those of such commercially available natural antioxidants as ascorbic acid, γ-oryzanol, gallic acid, l-tryptophan, (+)-catechin and d-α-tocopherol. The hydrogen- or electron-donating activities of procyanidins to the DPPH radical in a 50% ethanol solution were also stronger than those of ascorbic acid and d-α-tocopherol.

A new enzyme, proline acylase, extracted from a strain of Pseudomonas species has been purified to apparent homogeneity and has been shown to hydrolyze specifically N- acyl - l - proline derivatives such as N- acetyl - l - proline and chloroacetyl- l -proline. N -Acetylamino acids other than l -proline were unsusceptible, or nearly so. The enzyme also hydrolyzed the carboxyterminal proline residue in a peptide when its penultimate position was occupied by a glycine, such as Z-Gly- l Pro and Z-Gly- l Pro- l Leu-Gly- l Pro. It has a pH optimum at pH 6.0 and was inhibited by chelating reagent. The molecular weight was estimated to be 597 000 and 623 000 by sedimentation equilibrium and gel filtration, respectively. Upon disc electrophoresis in 1% SDS, the purified preparation migrates as a single band of molecular weight 55 000. The sedimentation coefficient and isoelectric point, determined by polyacrylamide gel electrophoresis, were s 20, w 0 = 18 S and pH = 5.0, respectively.

Further evidence for the glycoprotein nature of a 7S protein in soybean globulins was demonstrated by isolation of a glycopeptide from proteolytic digest. The homogeneity of the isolated glycopeptide was ascertained by amino-terminal analysis and high-voltage electrophoresis. This glycopeptide had a molecular weight of about 9870 and was composed of 17 amino acid residues (Asp6, Thr3, Gly3, Ala3, Glu1, Ser1) and 51 sugar residues (mannose39, glucosamine12). Considering that the content of carbohydrate moiety in this glycopeptide corresponds to that in the original protein, it may be concluded that the carbohydrate moiety is present in the protein as a single polysacchavide unit.

Soybean casein fraction was factionated by gel filtration with Sephadex G100. From the effluent diagram of soybean casein fraction, several minor components were obtained with a main component.One of them showed a single pattern by ultracentrifugal analysis, but it was found to be contaminated with RNA by column chromatography on DEAE-cellulose. From the result of purification by the repeated rechromatography, the purified component contained about 7% of RNA per protein. Therefore, it was considered to be a ribonucleoprotein.Among other minor components, free ribonucleic acids, which seemed to have different molecular weights were also present, but their ratios of purine to pyrimidine and base compositions coincided well each other.

Soybean casein fraction was factionated by gel filtration with Sephadex G100. From the effluent diagram of soybean casein fraction, several minor components were obtained with a main component.One of them showed a single pattern by ultracentrifugal analysis, but it was found to be contaminated with RNA by column chromatography on DEAE-cellulose. From the result of purification by the repeated rechromatography, the purified component contained about 7% of RNA per protein. Therefore, it was considered to be a ribonucleoprotein.Among other minor components, free ribonucleic acids, which seemed to have different molecular weights were also present, but their ratios of purine to pyrimidine and base compositions coincided well each other.

Various conditions were studied which gave influences on polyalcohol production by Pichia miso. Pichia miso gave an excellent yield of polyalcohol showing good growth in the vitamin-free medium. Unlike Zygosaccharomyces high concentrations of phosphate such as 2% as KH2PO4 in the medium showed no detrimental effect on polyalcohol production. Remarkable reduction in polyalcohol yield was observed in the medium of high concentration of nitrogen sources, among which yeast extract showed the most striking effect. Polyalcohol fermentation was provoked in the medium of 0.1% yeast extract while the metabolic activity distinctly converted to ethanol fermentation when the organisms were incubated in the medium of 4.0% yeast extract. The fact that a large amount of ethanol more than 6% in the medium was produced aerobically by genus Pichia of oxidative dissimilation type seemed to be very interesting and noticeable. For the purpose of industrial production, it was shown that polyalcohol production in jar-fermenter ...

A 7S protein in soybean globulins consisted of at least nine polypeptide chains (subunits). Complete dissociation into subunits, having a sedimentation coefficient of 1.1~1.4S and a molecular weight of 22,000~24,000, occurred in the presence of 8m urea and 4m guanidine hydrochloride. However, it was found by sedimentation, ultraviolet spectrophotometry and optical rotatory dispersion that the dissociation with various concentrations of urea accompanied simultaneously with the destruction of the internal structure of the protein. No disulfide bond appeared to participate in the binding between subunits from the results of sedimentation and disc electrophoresis. These results suggested that the subunits were very compactly and complicatedly folded on the formation of the gross structure, and hydrophobic bond with hydrogen bond also participated in the interaction between subunits.The dissociation was interfered with the increase of ionic strength using sodium chloride, particularly in low concentration of u...

Effects of pH, ionic strength, kind of salts and disulfide bond cleaving agent (2-mercaptoethanol) on conformation changes revealed on ultracentrifugal patterns of a 7S protein in soybean globulins were investigated. In the solution with lower pH than isoelectric point, this protein dissociated into two components in low ionic strength, but showed a 7S sedimentation pattern in higher ionic strength than 0.1. On the other hand, in the solution with higher pH than isoelectric point, this protoin showed aggregation to a 9S isomer in lower ionic strength than 0.1. Between ionic strength of 0.1 and 0.5, the mixture of 7S and 9S forms existed and in higher ionic strength than 0.5, the protein kept a 7S form stablely. These reactions were reversible and effect of 2-mercaptoethanol was scarcely observed but those of salts were observed.The molecular weight of the 9S isomer was approximately 370,000 and the s20,w value was 12.30S. Therefore, the 9S isomer was considered to be a dimer of the 7S protein.

Soybean, a native of China but now the most production in the United States, is well-known and much utilized throughout the world as an oil seed. Interest in soybeans for food uses has stimulated research and development in many laboratories. In particular, the protein constituent has been very important to our Japanese as the traditional soy foods such as soy sauce (shoyu), miso, tofu and so on. In contrast with the active application of soybean proteins for food use, the fundamental researches on soybean proteins (soybean globulins), owes much to works done during the past about twenty years. In this paper, I shall summarize the results of the biochemical investigations on soybean storage proteins, the composition, isolation and characterization of the protein constituents, their molecular structures and related problems.

The oxygen-dependent browning (oxidative browning) of Amadori compounds from amino acids or peptides was studied since it was an important reaction contributing to the discoloration and deterioration of some foodstuffs containing sugars and amino compounds during storage in contact with atmospheric oxygen.