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Titolo:
Unifying mechanism for Aplysia ADP-ribosyl cyclase and CD38/NAD(+) glycohydrolases
Autore:
Cakir-Kiefer, C; Muller-Steffner, H; Schuber, F;
Indirizzi:
ULP, Chim Bioorgan Lab, CNRS, UMR 7514, F-67400 Strasbourg, France ULP Strasbourg France F-67400 CNRS, UMR 7514, F-67400 Strasbourg, France
Titolo Testata:
BIOCHEMICAL JOURNAL
, volume: 349, anno: 2000,
parte:, 1
pagine: 203 - 210
SICI:
0264-6021(20000701)349:<203:UMFAAC>2.0.ZU;2-F
Fonte:
ISI
Lingua:
ENG
Soggetto:
ADENINE DINUCLEOTIDE GLYCOHYDROLASE; EGG-SPECIFIC NADASE; NAD+-GLYCOHYDROLASE; 2ND-MESSENGER ENZYME; CD38; PURIFICATION; HYDROLYSIS; SOLUBILIZATION; CYCLIZATION; METABOLISM;
Keywords:
cADP-ribose; cyclic ADP-ribose hydrolase; hydrolysis; methanolysis; NGD(+);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
33
Recensione:
Indirizzi per estratti:
Indirizzo: Schuber, F ULP, Chim Bioorgan Lab, CNRS, UMR 7514, 74 Route Rhin, F-67400 Strasbourg,France ULP 74 Route Rhin Strasbourg France F-67400 Strasbourg,France
Citazione:
C. Cakir-Kiefer et al., "Unifying mechanism for Aplysia ADP-ribosyl cyclase and CD38/NAD(+) glycohydrolases", BIOCHEM J, 349, 2000, pp. 203-210

Abstract

Highly purified Aplysia californica ADP-ribosyl cyclase was found to be a multifunctional enzyme. In addition to the known transformation of NAD(+) into cADP-ribose this enzyme is able to catalyst: the solvolysis (hydrolysisand methanolysis) of cADP-ribose. This cADP-ribose hydrolase activity, which becomes detectable only at high concentrations of the enzyme, is amplified with analogues such as pyridine adenine dinucleotide, in which the cleavage rate of the pyridinium-ribose bond is much reduced compared with NAD(+). Although the specificity ratio V-max/K-m is in favour of NAD(+) by 4 orders of magnitude, this multifunctionality allowed us to propose a 'partitioning' reaction scheme for the Aplysia in enzyme, similar to that establishedpreviously for mammalian CD38/NAD(+) glycohydrolases. This mechanism involves the formation of a single oxocarbenium-type intermediate that partitions to cADP-ribose and solvolytic products via competing pathways. In favour of this mechanism was the finding that the enzyme also catalysed the hydrolysis of NMN+, a substrate that cannot undergo cyclization. The major difference between the mammalian and the invertebrate enzymes resides in their relative cyclization/hydrolysis rate-constant ratios, which dictate their respective yields of cADP-ribose (ADP-ribosyl cyclase activity) and ADP-ribose(NAD(+) glycohydrolase activity). For the Aplysia enzyme's catalysed transformation of NAD(+) we favour a mechanism where the formation of cADP-ribose precedes that of ADP-ribose; i.e. macroscopically the invertebrate ADP-ribosyl cyclase conforms to a sequential reaction pathway as a limiting form of the partitioning mechanism.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 29/09/20 alle ore 14:03:12