Wall K A, Klis M, Kornet J, Coyle D, Amé J C, Jacobson M K, Slama J T
Department of Medicinal and Biological Chemistry, College of Pharmacy, University of Toledo, Toledo, OH 43606, USA.
Biochem J. 1998 Nov 1;335 ( Pt 3)(Pt 3):631-6. doi: 10.1042/bj3350631.
Carba-NAD and pseudocarba-NAD are carbocyclic analogues of NAD+ in which a 2,3-dihydroxycyclopentane methanol replaces the beta-d-ribonucleotide ring of the nicotinamide riboside moiety of NAD+ [Slama and Simmons (1988) Biochemistry 27, 183-193]. These carbocyclic NAD+ analogues, related to each other as diastereomers, have been tested as inhibitors of the intrinsic NAD+ glycohydrolase activity of human CD38, dog spleen NAD+ glycohydrolase, mouse CD38 and Aplysia californica cADP-ribose synthetase. Pseudocarba-NAD, the carbocyclic dinucleotide in which l-2,3-dihydroxycyclopentane methanol replaces the d-ribose of the nicotinamide riboside moiety of NAD+, was found to be the more potent inhibitor. Pseudocarba-NAD was shown to inhibit the intrinsic NAD+ glycohydrolase activity of human CD38 competitively, with Ki=148 microM determined for the recombinant extracellular protein domain and Ki=180 microM determined for the native protein expressed as a cell-surface enzyme on cultured Jurkat cells. Pseudocarba-NAD was shown to be a non-competitive inhibitor of the purified dog spleen NAD+ glycohydrolase, with Kis=47 miroM and Kii=198 microM. Neither pseudocarba-NAD nor carba-NAD inhibited mouse CD38 or Aplysia californica cADP-ribose synthetase significantly at concentrations up to 1 mM. The results underscore significant species differences in the sensitivity of these enzymes to inhibition, and indicate that pseudocarba-NAD will be useful as an inhibitor of the enzymic activity of human but not mouse CD38 in studies using cultured cells.
Carba-NAD和假Carba-NAD是NAD⁺的碳环类似物，其中2,3-二羟基环戊烷甲醇取代了NAD⁺烟酰胺核糖部分的β-D-核糖核苷酸环[斯拉马和西蒙斯（1988年），《生物化学》27卷，183 - 193页]。这些作为非对映异构体相互关联的碳环NAD⁺类似物，已被测试作为人CD38的内在NAD⁺糖水解酶活性、犬脾NAD⁺糖水解酶、小鼠CD38和加州海兔cADP - 核糖合成酶的抑制剂。假Carba-NAD，即l-2,3-二羟基环戊烷甲醇取代NAD⁺烟酰胺核糖部分的D-核糖的碳环二核苷酸，被发现是更有效的抑制剂。假Carba-NAD被证明可竞争性抑制人CD38的内在NAD⁺糖水解酶活性，对于重组细胞外蛋白结构域测定的Ki = 148微摩尔，对于在培养的Jurkat细胞上作为细胞表面酶表达的天然蛋白测定的Ki = 180微摩尔。假Carba-NAD被证明是纯化的犬脾NAD⁺糖水解酶的非竞争性抑制剂，Kis = 47微摩尔，Kii = 198微摩尔。在浓度高达1毫摩尔时，假Carba-NAD和Carba-NAD均未显著抑制小鼠CD38或加州海兔cADP - 核糖合成酶。这些结果强调了这些酶对抑制敏感性的显著物种差异，并表明在使用培养细胞的研究中，假Carba-NAD将作为人而非小鼠CD38酶活性的抑制剂发挥作用。
