2′-Phospho-Cyclic ADP-ribose, a Calcium-mobilizing Agent Derived from NADP

摘要: Abstract Cyclic adenosine diphosphoribose (cADPR), a metabolite of NAD, appears to modulate changes in intracellular free Ca levels by activation ryanodine-sensitive channels. We report here that an ADPR cyclase purified from Aplysia californica readily catalyzes the conversion NADP 2′-phospho-cyclic (2′-P-cADPR), cyclized at N-1 adenine moiety. An enzyme canine spleen previously shown contain NAD glycohydrolase, cyclase, and cADPR hydrolase activities also utilized 2′-P-cADPR as substrates. The apparent K value for was 1.6 μM compared with 9.9 V twice indicating is likely mammalian cells. active eliciting release rat brain microsomes, but unable elicit following 2′-P-ADPR action glycohydrolase. 1-D-myo-inositol 1,4,5-trisphosphate (IP) appear act distinct mechanisms microsomes desensitized IP still released response vice versa. Also, inhibition IP-induced heparin had no effect on 2′-P-cADPR. Both similar mechanism based kinetics release, dose-response curves, cross-desensitization, partial procaine. results this study suggest may function new component signaling possible link between metabolism homeostasis.