大麥種子之環狀單磷酸核苷的酵素水解

Enzymatic Hydrolysis of cyclic nucleoside monophosphate in Barley Seedlings

The enzymatic hydrolysis of cyclic nucleoside monophosphate in barley seedlings (Hordeum vulgare L., cultivar Himalaya) was investigated. Multiple forms of enzyme activity toward adenosine-2', 3'-cyclic monophosphate are observed. At least one of these is capable of catalyzing the hydrolysis of adenosine-3', 5'-cyclic monophosphate. Adenosine is the sole product from the hydrolysis of cyclic AMP because of the presence of nucleotidase activity. Further studies on substrate specificity, sedimentation behavior, pH optimum, metal ion effect, dithiothreitol effect and Km values suggest that the hydrolysis of cyclic nucleoside monophosphate may be due to a nonspecific acid phosphatase.