A DNA fragment coding for a decarbamylase protein improved in thermostability as the result of replacement of at least one base of a DNA fragment coding for a decarbamylase protein originating in a microbe with another base and the resultant replacement of at least one of the corresponding amino acids; a process for producing the fragment; a vector containing the fragment; a transformant produced with the vector; a decarbamylase improved in thermostability; and a process for producing the decarbamylase. Also disclosed is a process for producing a D-α-amino acid which comprises decarbamoylating an N-carbamoyl-D-α-amino acid with a decarbamylase having a thermostable temperature of 65° or above in an aqueous medium.
一种编码脱
氨基甲酰酶蛋白的DNA片段,由于用另一个碱基替换了编码源于微
生物的脱
氨基甲酰酶蛋白的DNA片段的至少一个碱基,并替换了至少一个相应的
氨基酸,从而提高了其耐热性;一种生产该片段的工艺;一种含有该片段的载体;一种用该载体生产的转化体;一种耐热性提高的脱
氨基甲酰酶;以及一种生产该脱
氨基甲酰酶的工艺。本发明还公开了一种生产 D-
α-氨基酸的工艺,该工艺包括在
水性介质中用脱
氨基酶使 N-
氨基甲酰-D-
α-氨基酸脱
氨基,脱
氨基酶的恒温温度为 65°或以上。