Yasutoyo Nagai

Phytase (myoinositolhexaphosphate phosphohydrolase) from Wheat Bran

Pure inositol tetra- and hexaphosphate were isolated as the main components of rice phytin by Dowex 1 column chromatography. Phytase of wheat bran was purified more than 1,500 folds. This phytase preparation showed 1) broad substrate specificity, 2) pH optimum at about 5.0, 3) no activation by magnesium ion, and 4) inhibition by fluoride ion for all the substrates tested; and was concluded as nonspecific acid phosphomonoesterase rather than phytin-specific phosphatase. The effects of metalic ions, thiol reagents, chelating agents, arsenate, alkylarsenate and hydrolysis products for this enzyme were studied. Michaelis constants and activation energy by this enzvme to various substrates were also calculated.

The Nutritional Efficiency of Cannibalism and an Artificial Feed for the Growth of Tadpoles of Japanese Toad: Bufo vulgaris sp

Tadpoles of Japanese toad (Bufo vulgaris) were cultured by an artificial feed and by forced cannibalism from the egg until metamorphosis finished. The best growth was found in the artificial feed group, however, the highest feed efficiency was observed in the cannibalism group. The tadpoles were metamorphosed by the culture with amino acid mixture feed but no body weight increase was seen in this case. The nutritional disturbance hindered the metamorphosis.The relative amino acid composition was constant throughout all the stages of the tadpole growth. The relative amino acid composition of the toad was diversed according to the species. Several unidentified ninhydrine-positive substances were detected on the column chromatograms of amino acid analysis of tadpoles and their adult forms.

Phytase from Wheat Bran

myo-Inositol mono-, di-, tri-, tetra-, and pentaphosphate were prepared by enzymic hydrolysis of myo-inositol hexaphosphate with a 1,500-fold purified phytase preparation from wheat bran and the subsequent Dowex 1 column chromatography. Relative initial rates of hydrolysis of these inositol phosphates by phytase were nearly the same each other and the activation energy of hydrolysis was about 11,000 cal. per mole for all these substrates. Km values did not vary widely with the substrates. The hydrolysis of inositol phosphates proceeded in a complicated way, except inositol monophosphate, where the reaction was of the first order. The enzyme hydrolyzed the substrates in the manner that removed phosphate group of them one by one. When mixed substrate was used the enzyme showed a preferential attack on the highest member of the phosphates present. From the mixed substrate test, it was concluded that wheat bran phytase is a single enzyme.

Allantoinase from Mung Bean Seedlings

Mung bean allantoinase was purified sixty folds by calcium phosphate gel treatment, ammonium sulfate fractionation and acetone precipitation. The purified allantoinase hydro-lyzed allantoin to allantoic acid almost completely and the reaction had a broad pH optimum between 7.5 and 8.3. The accumulation of allantoic acid during the germination of mung bean was also noted. The allantoic acid content of seedlings was higher in hypocotyl than in leaf and root.

Solubilization of Feather Keratin by a Copper-amine Complex: The Action of Cupri-ethylenediamine on Feather Keratin

Chicken feather keratin was solubilized by cupri-ethylenediamine treatment and the solubilized products were separated into acidic and basic fractions by ion exchangers. In the solubilized products which had a molecular weight between 10,000 and 60,000, all the original cystine residues disappeared and cysteic acid residues were recovered instead of them but partly. The cupri-ethylenediamine reagent which catalyzed air-oxidation of cystine residues in keratin was removable mostly from the products by dialysis against water. The common copper-amine complexes were ineffective to solubilize feather keratin except for Schweitzers reagent. One strongly basic, unusual amino acid was detected in the basic solubilized fraction. This amino acid was eluted after arginine by usual column chromatography.