Occurrence of d-amino acids in higher organisms: A survey of the distribution of d-amino acids in marine invertebrates

Abstract

1. 1. d-amino acids assayed using a d-amino acid oxidase (DAO) technique have been found in 18 species of marine invertebrates in six phyla out of a total of 43 species in eight phyla that were analyzed (42%). 2. 2. The apparent tissue concentrations ranged from 44 mM in the polychaete, Glycera dibranchiata to 0.04 mM in the nemertine, Parborlasia corrugatus. 3. 3. Endogenous inhibitors (mol. wt 1000–2000 as determined by gel filtration) were discovered which drastically decrease the sensitivity of the DAO assay technique. It is therefore possible that the reported concentrations are underestimates of the true tissue concentrations. 4. 4. Their wide distribution in marine invertebrates suggests there may be undiscovered physiological and nutritional roles for d-amino acids.