OPINE OXIDOREDUCTASES IN BRACHIOPODS, BRYOZOANS, PHORONIDS AND MOLLUSKS

The opine dehydrogenases catalyse the reductive condensation of pyruvate with various amino acids to form products resembling octopine (N-carboxyethyl arginine). They are widely distributed among marine invertebrates and function in metabolism in the place of lactate dehydrogenase, which often has very low activity, especially in molluscs. The reaction of pyruvate, both alone and with either alanine, arginine, beta-alanine, or taurine, catalysed by tissue extracts of various species, was measured by decrease in absorbance of NADH. The 27 species examined were brachiopods, bryozoans, phoronids and a wide variety of molluscs, including a scaphopod, two chitons and species representing the five subclasses of bivalves and three orders of prosobranch gastropods. Activities were coded 0-5, with 5 assigned to rates greater than 5-mu-mol min-1 g-1. These numbers were entered by species into a program that performed average linkage cluster analysis. Results of this analysis were transformed into a dendrogram. The plesiomorphic state was defined as the presence of the total array of opine enzymes and the loss of one or more during evolution was taken as apomorphic. The resulting dendrogram has some features in common with standard phylogenetic trees based on morphology and development.