Enzymatic N-Acetylation of Lysine Analogs
PURIFICATION AND PROPERTIES OF ACETYL COENZYME A:S-(
-AMINOETHYL)-l-CYSTEINE 
-N-ACETYLTRANSFERASE
Hidehiko Tanaka 1 and Kenji Soda 1
From the
1 From the Laboratory of Microbial Biochemistry, Institute for Chemical Research, Kyoto University, Uji, Kyoto-Fu 611, Japan
Acetyl-CoA: S-(ß-aminoethyl)-l-cysteine -N-acetyltransferase, an enzyme catalyzing the transfer of acetyl group from acetyl-CoA to the terminal amino group of S-(ß-aminoethyl)-l-cysteine, a metabolic antagonist of l-lysine, has been purified about 450-fold from the cell-free extracts of Aerobacter aerogenes. The purified enzyme is homogeneous by the criterion of disc gel electrophoresis and has an approximate molecular weight of 100,000. In addition to S-(ß-aminoethyl)-l-cysteine, its d-enantiomer, sulfoxide, sulfone, and higher homolog, and an oxygen analog of lysine, O-(ß-aminoethyl)-dl-serine act as acetyl acceptors. l- or d-Lysine and l- or d-ornithine also can accept an acetyl group to a certain extent, but 
- or -N-acetylated derivatives of both S-(ß-aminoethyl)-l-cysteine and l-lysine are not active. Acetyl-CoA is the exclusive acyl donor in the transfer reaction. The following apparent Michaelis constants were determined: S-(ß-aminoethyl)-l-cysteine, 2.1 x 10-3 m; S-(ß-aminoethyl)-d-cysteine, 1.6 x 10-3 m; O-(ß-aminoethyl)-dl-serine, 1.7 x 10-3 m; S-(ß-aminoethyl)-l-homocysteine, 7.1 x 10-4; and acetyl-CoA, 4.5 x 10-3 m. The enzyme activity is inhibited competitively in propionyl-CoA, butyryl-CoA, and benzoyl-CoA against acetyl-CoA. S-(ß-Aminoethyl)--N-acetyl-l-cysteine and S-(ß-aminoethyl)-mercaptopropionate are strong competitive inhibitors of S-(ß-aminoethyl)-l-cysteine acetylation.
Submitted on January 2, 1974
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