Detail of "16719-36-1"

Reference

Cyclic nucleotide derivatives as probes of phosphodiesterase catalytic and regulatory sites

Cyclic nucleotide derivatives as probes of phosphodiesterase catalytic and regulatory sites. Erneux, Christophe; Couchie, Dominique; Dumont, Jacques E.; Jastorff, Bernd (Hop. Erasme, Univ. Libre Bruxelles, Brussels B-1070, Belg.). Adv. Cyclic Nucleotide Protein Phosphorylation Res., 16, 107-18 (English) 1984. CODEN: ACNREY. DOCUMENT TYPE: Journal CA Section: 7 (Enzymes) Various structural aspects of the calmodulin-stimulated and cGMP-stimulated forms of cyclic 3',5'-nucleotide phosphodiesterase (I) were studied. The 2 forms could be differentiated on the basis of their inhibition by a series of cAMP and cGMP derivs. Thus, the 2 forms have distinct catalytic sites. The concns. of 3'-amino-3'-deoxyguanosine 3',5'-monophosphate and 7-deazaguanosine 3',5'-monophosphate needed to stimulate cGMP-sensitive I 2-fold (0. 16719-36-1 and 90320-05-1 are cas registry numbers of chemicals which are used as reagents here.02 and 1 mM, resp.) were lower than those of the corresponding adenosine analogs. Thus, the activating site of this enzyme is better able to distinguish and recognize a guanine-type base structure. MIX (1-methyl-3-isobutylxanthine) (3-50 mM) stimulated basal cGMP-stimulated I (rat liver enzyme) in the presence of low levels of substrate, cAMP, and in the absence of cGMP. At higher cAMP concns. (100 mM), MIX was inhibitory. MIX was a pure competitive inhibitor when cGMP was used as substrate or was present as enzyme activator. The behavior of 6-chloropurine 3',5'-monophosphate was similar to that of MIX, whereas benzimidazole 3',5'-monophosphate was an activator (lowering Km values) under all conditions. Thus, whereas MIX must bind to the catalytic site of I, benzimidazole 3',5'-monophosphate (as well as cGMP itself) must follow another mechanism of activation, presumably involving a distinct regulatory site. .