Alanine carboxypeptidase

This chapter describes the structural chemistry and the biological aspects of alanine carboxypeptidase. The chapter discusses that characterization of enzymes hydrolyzing folate analogs led Levy & Goldman (1969) to synthesize other such compounds for screening soil cultures. The folate analog 4-amino-4-deoxypteroyl alanine and subsequently 4-aminobenzoyl alanine were synthesized. Later, Miyagawa (1986) sought to isolate enzymes related to hippuryl hydrolase (N-benzoylglycine hydrolase). N-Benzoyl-L-alanine was used to isolate an enzyme from the soil microorganism Corynebacterium equi H-7. The name alanine carboxypeptidase was adopted by the Enzyme Commission to describe these enzymes isolated from soil bacteria. The enzyme from Corynebacterium equi H-7 was referred to as N-benzoyl-L-alanine amidohydrolase. Levy & Goldman purified their enzyme more than 100-fold to near homogeneity by classical techniques. Miyagawa purified the enzyme 323-fold to apparent homogeneity by classical techniques, that is, ammonium sulfate fractionation, and sequential chromatography on DEAE-cellulose, DEAE-Sephadex A50 and hydroxyapatite. The enzyme described by Miyagawa behaves as an atypical hippuryl hydrolase, preferring Bz-Ala over Bz-Gly.