G. S. Dhillon, T. Nagasawa, H. Yamada
May 1, 1984
Citations
0
Influential Citations
10
Citations
Journal
Journal of Biotechnology
Abstract
Summary A bacterial strain that shows resistance to 3-chloro-L-alanine was isolated from the soil and identified as Bacillus sphaericus L-118. The crude extract of this organism has an enzyme that can catalyze the β-replacement reaction of 3-chloro- l -alanine in the presence of a high concentration of sodium hydrosulfide to form l -Cysteine. The l -cysteine-synthesizing activity increased with an increase in 3-chloro- l -alanine in the medium. l -Cysteine-synthesizing enzymes were purified from the cells obtained by cultivating B. sphaericus L-118 in the absence or presence of 3-chloro- l -alanine and both enzymes appeared to be homogeneous. Both enzymes exhibited the same molecular weight (about 68000), two subunits identical in molecular weight (about 34000), Km values (14.5 mM for 3-chloro- l -alanine, 7.8 mM for O-acetyl- l -serine), isoelectric point (pH 4.5), substrate specificity, immunological properties and elution patterns on DEAE-cellulose, and were confirmed to be same enzyme. Further, it has been established that the l -cysteine-synthesizing enzyme was O-acetylserine sulfhydrylase.