Serine racemase (SR) catalyses two reactions: the reversible racemisation of L-serine and the irreversible dehydration of L- and D-serine to pyruvate and ammonia.
Human serine racemase is a pyridoxal 5'-phosphate (PLP)-dependent dimeric enzyme that catalyzes the reversible racemization of L-serine and D-serine and their dehydration to pyruvate and ammonia.
SDH (l-serine dehydratase, EC 4.3.1.17) is a pyridoxal-5'-phosphate (PLP)-dependent enzyme that catalyzes dehydration of l-Ser/Thr to yield pyruvate/ketobutyrate and ammonia.