Lysine 2,3-aminomutase: role of S-adenosyl-L-methionine in the mechanism. Demonstration of tritium transfer from (2RS,3RS)-[3-3H]lysine to S-adenosyl-L-methionine

Abstract

(2RS,3RS)-[3-³H]Lysine has been synthesized, and incubated with lysine 2,3-aminomutase in the presence of S-adenosyl-L-methionine (SAM). After incubation, the SAM was converted, by heating, into methylthioadenosine (MTA). The latter contained ca. 1–6% of the incubated tritium, consistent with an exchange of SAM hydrogens (probably at C-5′) with the 3-pro-R hydrogen of lysine. The results support a mechanism for lysine 2, 3-aminomutase in which SAM acts as hydrogen carrier.