کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1940274 | 1050778 | 2006 | 8 صفحه PDF | دانلود رایگان |
ADP-ribosyl cyclases (ADPRCs) are present from lower Metazoa to mammals and synthesize the Ca2+-active (di)nucleotides cyclic ADP-ribose (cADPR), NAADP+, and ADP-ribose (ADPR), involved in the regulation of important cellular functions. NAADP+ can be synthesized by ADPRCs from NADP+ through a base-exchange reaction, which substitutes nicotinamide for nicotinic acid (NA). Here we demonstrate that ADPRCs from both lower and higher Metazoa (including human CD38) can also synthesize NAADP+ starting from 2′-phospho-cyclic ADP-ribose (cADPRP) and NA. Comparison, on the two substrates cADPRP and NADP+, of the relative rates of the reactions introducing NA and hydrolyzing/cyclizing the substrate, respectively, indicates that with all ADPRCs tested cADPRP is preferentially transformed into NAADP+, while NADP+ is preferentially cyclized or hydrolyzed to cADPRP/2′-phospho-ADP-ribose. cADPRP was detectable in retinoic acid-differentiated, CD38+ HL-60 cells, but not in undifferentiated, CD38− cells. These results suggest that cADPRP may be a NAADP+ precursor in ADPRC+ cells.
Journal: Biochemical and Biophysical Research Communications - Volume 345, Issue 2, 30 June 2006, Pages 573–580