白米中のジメチルスルフィド前駆物質の分離, 同定と酵素による分解 : 古米使用清酒の特異臭に関する研究(第12報)

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Dimethyl sulfide (DMS)-precursor in rice was extracted successively with H_2O, 0.5M NaCl, 70% EtOH and 0.05N NaOH. Most of the precursor was found to be present in the glutelin fraction by Sephrose 4B column chromatography of the SDS-2-mercaptoethanol extract of the crude fraction.Crude protein treated with α-amylase from Bacillus subtilis was hydrolyzed with HCl. DMS-precursor in HCl hydrolyzate was purified repeatedly by Bio-Gel P-2,Dowex 50-X4 (H^+), Amberlite IRA 411 (OH^-) and IRC-50 (H^+) column chromatography and crystallized as its picric acid salt. The amino acid composition of purified DMS-precursor, and the melting point and IR spectrum of its picrate were identical with those of authentic methyl methionine sulfonium chloride (MMS) and its picrate. Enzymic digests of crude protein with Sumyzyme AP (pH 4.0) and Pronase E (pH 9.0) were lyophilized and applied to a Bio-Gel P-2 column. Two peaks of DMS precursor were detected by the heat and heat-alkali methods, and these were suggested to be the same as peaks 1 and 2 of the precursor in sake reported previously.
社団法人日本生物工学会の論文
1982-01-25