IDENTIFICATION OF BETA-TRACE AS PROSTAGLANDIN-D SYNTHASE

Human cerebrospinal fluid (CSF) is the richest source of prostaglandin (PG) D synthase, a key enzyme in sleep regulation, having a specific activity of 20-130 nmol/min/mg protein that is almost two orders of ma gnitude higher than that of crude rat brain homogenate (2-7 nmol/min/m g protein). PGD synthase was purified from human CSF approximately 8-f old to apparent homogeneity in a yield of 6% by ammonium sulfate fract ionation followed by column chromatographies on phenyl-Sepharose and D EAE-cellulose. The purified enzyme displayed enzymatic properties almo st identical to those of rat brain PGD synthase in terms of Mr, specif ic activity, optimum pH, Km value, and SH requirement. The purified PG D synthase cross-reacted with an antibody against rat brain PGD syntha se and also with that against human p-trace, a major protein in the CS F. Furthermore, beta-trace cross-reacted with rat brain PGD synthase a ntibody. The N-terminal sequences of human PGD synthase, beta-trace, a nd purified PGD synthase from human CSF were essentially identical. Th ese results clearly show that beta-trace is structurally and enzymolog ically identical to PGD synthase. (C) 1994 Academic Press, Inc.