Inhibition of growth of Salmonella typhimurium and of threonine deaminase and transaminase B by beta-chloroalanine.

beta-Chloro-l-alanine (CA) was found to inhibit the growth of Salmonella typhimurium. The inhibition was overcome by isoleucine plus valine. CA inhibited the activity of threonine deaminase and transaminase B in vitro. The inhibition of threonine deaminase was reversible and was not affected by desensitization to isoleucine inhibition. Transaminase B was irreversibly inactivated. Derepression of some of the isoleucine and valine biosynthetic enzymes was achieved by growth of wild-type cells on low levels of CA.