1. 1. Strombine dehydrogenase from the adductor muscle of the marine mussel Modiolus squamosus was partially purified by ammonium sulfate fractionation, gel filtration and chromatography on Procion Red Agarose. 2. 2. The enzyme showed relatively broad amino acid specificity using glycine, alanine, cysteine, and glutamate in order of decreasing activity. 3. 3. In terms of keto-acid specificity, this enzyme utilized pyruvate, oxaloacetate, α-ketobutyrate and glyoxylate in order of decreasing activity. 4. 4. The strombine dehydrogenase from M. squamosus has catalytic properties similar to other marine invertebrate alanopine/strombine dehydrogenases. This enzyme appears to function during periods of elevated energy demand. © 1984.