Molecular cloning and functional expression of bovine spleen ecto-NAD+ glycohydrolase: structural identity with human CD38

Abstract

Bovine spleen ecto-NAD + glycohydrolase, an archetypal member of the mammalian membrane-associated NAD(P) + glycohydrolase enzyme family (EC 3.2.2.6), displays catalytic features similar to those of CD38, i.e. a protein originally described as a lymphocyte differentiation marker involved in the metabolism of cyclic ADP-ribose and signal transduction. Using amino acid sequence information obtained from NAD + glycohydrolase and from a truncated and hydrosoluble form of the enzyme (hNADase) purified to homogeneity, a full-length cDNA clone was obtained. The deduced sequence indicates a protein of 278 residues with a molecular mass of 31.5 kDa. It predicts that bovine ecto-NAD + glycohydrolase is a type II transmembrane protein, with a very short intracellular tail. The bulk of the enzyme, which is extracellular and contains two potential Nglycosylation sites, yields the fully catalytically active hNADase which is truncated by 71 residues. Transfection of HeLa cells with the full-length cDNA resulted in the expression of the

Kinetic competence of the cADP-ribose‒CD38 complex as an intermediate in the CD38/NAD+ glycohydrolase-catalysed reactions: implication for CD38 signalling

“…and K m , or were approximated. The values for k # and k −% , that correspond to the rate-limiting formation of the ADPribosyl oxocarbenium intermediate from NAD + and cADPR respectively [13,26,27] (and see above), were calculated from their respective V max values (Table 1) using 32 kDa as the molecular mass of the enzyme [17,23]. The constants k −" and k & were deduced from the approximation that K m l K s [26] (see Table 1).…”

The NAD-glycohydrolase (nga) gene of Streptococcus pyogenes

“…The DNA products were sequenced directly and several nucleotide changes re£ecting conservative amino acid substitutions were detected in the nga ORF. One nonconservative amino acid substitution was detected which was located upstream of the protein sequence that, by homology, resembles the predicted CD38 catalytic domain [20] (Fig. 3A).…”

Evidence for an Intracellular ADP-ribosyl Cyclase/NAD+-glycohydrolase in Brain from CD38-deficient Mice

“…Enzymatic 30. Aliquots of 50 -100 l were injected and eluted isocratically at room temperature with a medium containing 10 mM ammonium phosphate buffer at pH 5.5 and 1% (v/v) acetonitrile.…”