101. Metabolism of cyclic ADP-ribose: Zinc is an endogenous modulator of the cyclase/NAD glycohydrolase ratio of a CD38-like enzyme from human seminal fluid.
- Author
-
Zielinska W, Barata H, and Chini EN
- Subjects
- ADP-ribosyl Cyclase isolation & purification, ADP-ribosyl Cyclase 1, Adult, Animals, Antigens, CD isolation & purification, Biological Assay, Blotting, Western, Chromatography, High Pressure Liquid, Dose-Response Relationship, Drug, Edetic Acid pharmacology, Humans, Male, Membrane Glycoproteins, Sea Urchins, Semen chemistry, Semen drug effects, Zinc pharmacology, ADP-ribosyl Cyclase metabolism, Antigens, CD metabolism, Cyclic ADP-Ribose metabolism, NAD+ Nucleosidase metabolism, Semen enzymology, Zinc metabolism
- Abstract
CD38, a bifunctional enzyme capable of both synthesis and hydrolysis of the second messenger cyclic ADP-ribose (cADPR). Using the natural substrate of the enzyme, NAD+, the ratio of ADP-ribosyl cyclase/NAD glycohydrolase of CD38 is about 1/100. Here we describe that human seminal fluid contain a soluble CD38 like enzyme with an apparent M.W. of 49 kDa. When purified this enzyme has a cyclase/NAD glycohydrolase ratio of about 1/120. However, the in situ cyclase/NAD glycohydrolase ratio measured in seminal plasma approaches 1/1. We also found that physiological concentrations of zinc present in the seminal fluid, in the range of 0.6 to 4 mM, are responsible for the modulation of the cyclase/NAD glycohydrolase ratio. This new information indicates that the cyclase/NAD glycohydrolase ratio can be modified in vivo.
- Published
- 2004
- Full Text
- View/download PDF