In order to study specificity of pancreatic lipase, a number of synthetic triglycerides were hydrolyzed by the enzyme under an improved condition. The proportions of isomers of the derived mono- and diglycerides, and the fatty acid compositions of the derived free acids and monoglycerides were determined. The hydrolyzing rate of fatty acids in glycerides depended on the position esterified in the glycerol, carbon number of the acid, and structure of the glyceride. Positional specificity of the enzyme was markedly displayed for symmetrical triglycerides composed of long chain acids, but at somewhat lower rate for glycerides containing short chain or highly unsaturated acids.

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The distribution of fatty acids in the triglycerides of animal and vegetable fats was investigated, using an improved method of hydrolysis by pancreatic lipase. All individual saturated acids in vegetable fats occupied exclusively the outside positions of glycerol molecule except lauric acid in coconut oil, whereas unsaturated acids predominantly located at the 2 position. In animal fats, a partial pattern of distribution depending on the carbon-chain length of fatty acids was observed, in which lower acid showed a higher concentration at the 2 position and higher acids at the outside positions except some unsaturated fatty acids.

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A natural activator occurring in the aged pupae of the housefly, Musca domestica Maquart, was partially purified by means of fractionation with ammonium sulfate and of lyophilization. The preparation of the activator without accompanying tyrosinase activity made it possible to devise a method for measuring its activity, i. e., a partially purified protyrosinase which contained no activator was incubated together with natural activator, and the formation of tyrosinase activity was followed either manometrically or colorimetrically. Effects of concentration of natural activator, pH and temperature on the activation of protyrosinase were studied, resulting in an assumption that the activation occurs catalytically. Inhibition of the activation by various chemical reagents were studies and it was found that sodium picryl sulfate, N-bromosuccinimide or iodine inactivated natural activator irreversibly, and thioglycol or monoiodoacetate inhibited considerably. However, these reagents have almost no effect on the potential activity of protyrosinase. As the results, it was presumed that natural activator is an enzyme and protyrosinase is its substrate. The mode of activation of protyrosinase by the activator is, however, still obscure.

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Two kinds of proteolytic enzyme, tentatively named acid protease A and B which showed a single peak on electrophoresis individually, were isolated from the crude enzyme powder obtained from the broth filtrate cultured with Aspergillus niger var. macrosporus. Acid protease B is similar too the fungal acid protease previously reported, because the enzyme exhibits optimum activity on milk casein at about pH 2.6 and 55°C when the incubation was done at pH 2.6. Acid protease A is a new proteolytic enzyme, because the enzyme exhibits optimum activity on milk casein at about 2.0 and 70°C or 60°C when the incubation was done at pH 2.6 or 1.5 respectively.

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A new synthetic method of purine glucosides was described. Fusion of bis-trimethylsilyl-N-ben-zoyladenine and -hypoxanthine with α-acetobromoglucose and subsequent removal of the protecting groups gave glucopyranosyladenine and -hypoxanthine, respectively. In the former, the formation of α-glucoside was confirmed. Nuclear magnetic resonance spectra of the pyrimidine and purine glucosides were also reported.

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Two glucosides of coumarin derivatives were separated from sweet potato roots with black rot, by the combination of silica gel-coated thin layer chromatography and paper chromatography, and identified with skimmin and scopolin. The magnitude of synthesis of both bound coumarins was lower than that of the corresponding free coumarins, whereas they were detectable in neither cut nor fresh root tissues.

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The process of apple juice clarification by pectolytic enzymes has been successfully observed turbidimetrically and macroscopically by heating of reaction mixtures. It has been shown that the process of apple juice clarification varies with the varieties and conditions of apple juices as well as with the sources of enzyme preparations. From a study of the turbidimetry of apple juice clarification, a method for determination of clarification values been described.

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Several gibbane-l0-carboxylic acids and esters, including methyl (±)-desoxogibberate and methyl (±)-desoxoepigibberate, were synthesized.

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Two compounds with a novel tetracyclic skeleton, (±)-1, 7-dimethyl-5-oxoisogibba-A-triene and (±)-1, 7-dimethylisogibba-A-triene, were synthesized.

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To pick out potent strains which specifically produce one of several pectic enzymes, endo- and exo-polygalacturonase, pectin esterase, macerating, and apple juice clarifying activities were examined with regard to 344 strains of mold (containing 71 strains of phytopathogenic mold) grown on a bran culture medium and 56 strains of shakingly cultured yeast. As the result of screening, Aspergillus saitoi and Penicillium islandicum were isolated as potent specific producers of endo-polygalacturonase. And the composition of pectic enzymes of mold was found to be rather genus or species specific. So far as examined in crude enzyme systems, there was no parallelism between any one of pectic enzyme activities and apple juice clarifying or macerating activities.

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