Biochemical properties of carboxypeptidase from Aloe arborescens Miller var. natalensis Berger

A carboxypeptidase was partially purified from Aloe arborescens Miller var. natalensis Berger on a scale suitable for pharmacological studies. The enzyme was most active and stable at pH 5.0. The enzyme had a broad specificity against various synthetic peptides, being capable of splitting C‐terminal proline. Its activity was inhibited almost completely by diisopropylfluorophosphate, strongly by transition metals, such as Fe3+, Hg2+ and Cu2+, and moderately by sulphydryl reagents. These results indicate that Aloe enzyme is a serine carboxypeptidase and appears to contain a sulphydryl group that may be involved in its inactivation.