In vitro studies on L-serine deaminase activity of Escherichia coli K12.

Extracts of Escherichia coli K12 contain an enzyme which deaminates L-serine. This serine deaminase appears to be a soluble enzyme and is inhibited by substrate analogues, metal ions, and chelators. The activity, which is very unstable in vitro, is protected, and in some cases, even activated by substrate, substrate analogues, and by ferrous ion. The enzyme has proved unstable in all attempts at purification. It resembles closely the L-serine deaminase activity in other microorganisms, but is very different from the mammalian enzyme. As judged by comparison with organisms in which this enzyme serves as part of the principal carbon-handling pathway, L-serine deaminase activity is present in E. coli extracts in physiologically significant amounts.