Enzymes in Ontogenesis (Orthoptera). III. Activation of Naturally Occurring Enzymes (Tyrosinase).

Abstract

Interest in the enzyme tyrosinase seems largely to have centered around its distribution as well as the nature of its action on various natural and artificial substrates. Its rather wide occurrence in plants seems well established while for animals data are available which would lead one to assume a rather limited or restricted distribution (Graubard and Nelson,1 v. Euler,2 Graubard,3 Raper4). Insects appear to be rich in the enzyme (Bodine and Boell5).The present paper treats of results of a study on the growth, activation and substrate relations of tyrosinase as found in the developing egg of the grasshopper, Melanoplus differentialis. The advantages in using such biological material have been previously indicated and mention will only be made where departures from usual procedures occur.5 Enzyme preparations were obtained from centri-fuged fractions of egg brei after the following manner. For each set of experiments, 200 eggs of known age were removed from pods and carefully selected for morphological ...