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Title 

Kinetic study on the enzymatic production of D-alanine from D-aspartic acid

Authors 

Jae Heung LeeMoon Hee SungYeong Joong Jeon

Publisher 

Microbiological Society of Korea

Issue Date 

2002

Citation 

Journal of Microbiology, vol. 40, no. 1, pp. 33-37

Keywords 

competitive inhibitionD-alanineD-amino acid aminotransferaseD-aspartic acidping pong mechanismdextro alaninedextro amino acid aminotransferasedextro aspartic acidglyoxylic acidpyruvic acid

Abstract 

An enzymatic reaction for the production of D-alanine from D-aspartic acid and pyruvate as substrates by a thermostable D-amino acid aminotransferase (D-AAT) was investigated at various conditions in the temperature range of 40-70°C and pH range of 6.0-9.5. The D-AAT was produced with recombinant E. coli BL21, which hosted the chimeric plasmid pTLK2 harboring the D-AAT from the novel thermophilic Bacillus sp. LK-2. The enzyme reaction was shown to follow the Ping Pong Bi Bi mechanism. The Km values for D-aspartic acid and pyruvate were 4.38 mM and 0.72 mM, respectively. It was observed that competitive inhibition by D-alanine, the product of this reaction, was evident with the inhibition constant Ki value of 0.1 mM. A unique feature of this reaction scheme is that the decarboxylation of oxaloacetic acid, one of the products, spontaneonsly produces pyruvate. Therefore, only a catalytic amount of pyruvate is necessary for the enzyme conversion reaction to proceed. A typical time-course kinetic study showed that D-alanine up to 88 mM could be produced from 100 mM of D-aspartic acid with a molar yield of 1.0.

ISSN 

1225-8873

Appears in Collections

1. Journal Articles > Journal Articles

Registered Date

2017-04-19


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