Purification and immunochemical analysis of histidine decarboxylase from murine mastocytoma

Application of a new scheme of purification for histidine decarboxylase (E.C. 4.1.22) leads to a highly purified enzyme (5000 nmol/mg . h, i.p. 5.0, M.2.: 110 kD) with reasonable stability (rest activity 80% after 3 weeks at 6--8 degrees C). A major protein contaminant seen on electrofocusing (i.p. 4.6) shows immunological identity with the enzyme-containing protein (i.p. 5.0) and might be involved in the aggregation of the enzyme.