Enzymology of Ca[sup.2+]-Mobilizing Second Messengers Derived from NAD: From NAD Glycohydrolases to NADPH Oxidases

Nicotinamide adenine dinucleotide (NAD) and its 2′-phosphorylated cousin NADP are precursors for the enzymatic formation of the Ca[sup.2+] -mobilizing second messengers adenosine diphosphoribose (ADPR), 2′-deoxy-ADPR, cyclic ADPR, and nicotinic acid adenine dinucleotide phosphate (NAADP). The enzymes involved are either NAD glycohydrolases CD38 or sterile alpha toll/interleukin receptor motif containing-1 (SARM1), or (dual) NADPH oxidases (NOX/DUOX). Enzymatic function(s) are reviewed and physiological role(s) in selected cell systems are discussed.