STUDIES ON BEEF SPLEEN CATHEPSIN A

Abstract
Beef spleen extracts contain enzymic activity toward carbobenzoxy-L-glutamyl-L-tyrosine and carbobenzoxy-L-glutamyl-L-tyrosylglycine, the glutamyl-tyrosyl bond being cleaved in both cases. This action is similar to that of pepsin on these substrates, and is assigned to the spleen enzyme designated cathepsin A, which acts optimally near pH 5.7 and does not require activation by sulfhydryl compounds.