We have found that in the secretion of rat anterior prostate, a hydrolyzing activity on GTP is present with a high affinity for the substrate; ATP, GDP, and ADP are not substrates for enzymatic activity. At the same time we have shown that GTP is a negative modulator for the well-known type IV transglutaminase activity present in the prostatic secretion. The hydrolyzing activity on GTP appears to be due to two molecular species: a high-molecular-weight GTPase, having electrophoretical mobility higher than 100 kDa, and a low-molecular-weight GTPase, of about 30 kDa. The two enzymatic activities are associated in the prostatic secretion with the transglutaminase (type IV). We describe an experimental procedure to separate them.
Copyright 1999 Academic Press.