Murooka Y, Kakihara K, Miwa T, Seto K, Harada T
J Bacteriol. 1977 Apr;130(1):62-73. doi: 10.1128/jb.130.1.62-73.1977.
An enzyme that can synthesize O-alkylhomoserine from alcohols and O-acetylhomoserine was purified from Corynebacterium acetophilum. The enzyme was found to be identical to O-acetylhomoserine sulfhydrylase; a preparation that appeared homogeneous on polyacrylamide gel electrophoresis showed both O-alkylhomoserine-synthesizing and O-acetylhomoserine sulfhydrylase activities. Its molecular weight was determined to be about 220,000, and it consisted of two subunits. Its pH and temperature optima for the two reactions were the same. Besides catalyzing the formation of homocysteine from O-acetylhomoserine and sulfide, it also catalyzed the syntheses of O-alkylhomoserines corresponding to the alcohols added form O-acetylhomoserine and ethyl alcohol, n-propylalcohol, n-butyl alcohol, methyl alcohol, and n-pentyl alcohol, its activities with these alcohols decreasing in that order. L-Homoserine, O-succinylhomoserine, and O-acetylserine reacted with sulfide. O-ethylhomoserine, O-acetylthreonine, O-succinylhomoserine, and O-acetylserine inhibited both enzyme activities. O-acetylhomoserine sulfhydrylase purified from Saccharomyces cerevisiae also showed O-alkylhomoserine-synthesizing activity. Thus, O-acetylhomoserine sulfhydrylase seems to catalyze O-alkylhomoserine synthesis in the presence of appropriate concentrations of alcohol and O-acetylhomoserine in microorganisms.
从嗜乙酸棒杆菌中纯化出一种能从醇类和O - 乙酰高丝氨酸合成O - 烷基高丝氨酸的酶。发现该酶与O - 乙酰高丝氨酸巯基酶相同；在聚丙烯酰胺凝胶电泳上呈现均一性的制剂同时具有合成O - 烷基高丝氨酸和O - 乙酰高丝氨酸巯基酶的活性。其分子量测定约为220,000，由两个亚基组成。这两种反应的最适pH和温度相同。除了催化由O - 乙酰高丝氨酸和硫化物形成高半胱氨酸外，它还催化从O - 乙酰高丝氨酸与加入的乙醇、正丙醇、正丁醇、甲醇和正戊醇相应的O - 烷基高丝氨酸的合成，其对这些醇类的活性按此顺序降低。L - 高丝氨酸、O - 琥珀酰高丝氨酸和O - 乙酰丝氨酸与硫化物反应。O - 乙基高丝氨酸、O - 乙酰苏氨酸、O - 琥珀酰高丝氨酸和O - 乙酰丝氨酸抑制这两种酶活性。从酿酒酵母中纯化的O - 乙酰高丝氨酸巯基酶也显示出合成O - 烷基高丝氨酸的活性。因此，在微生物中，在适当浓度的醇类和O - 乙酰高丝氨酸存在下，O - 乙酰高丝氨酸巯基酶似乎催化O - 烷基高丝氨酸的合成。
