A specific, low Km ADP-ribose pyrophosphatase from rat liver.
Two rat liver ADP-ribose pyrophosphatases (ADPRibases) were partially purified. ADPRibase-I hydrolyzed ADP-ribose (Km = 0.5 microM) giving AMP as a product, required Mg2+ or, less efficiently, Mn2+ (Ca2+ was not active), its activity changed little between pH 7 and 9, and was specific for ADP-ribose as it did not hydrolyze ADP-glucose, NAD+, NADH or diadenosine 5',5"'-P1,Pn-n-phosphates (Ap2A, Ap3A). ADPRibase-II showed similar properties, except that the Km for ADP-ribose was 50 microM and may be non-specific, as the same preparation hydrolyzed ADP-glucose, NADH and Ap2A. ADPRibase-I fulfills the requirements of a specific turnover pathway consistent with a cellular role for free ADP-ribose.
Miró
A
A
Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Medicina, Universidad de Extremadura, Badajoz, Spain.
Costas
M J
MJ
García-Díaz
M
M
Hernández
M T
MT
Cameselle
J C
JC
D000245:Adenosine Diphosphate Glucose / Q000378:metabolism; D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000818:Animals; D015226:Dinucleoside Phosphates / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008099:Liver / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D009243:NAD / Q000378:metabolism; D011755:Pyrophosphatases / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D013379:Substrate Specificity
D015226:Dinucleoside Phosphates; D009243:NAD; C012276:diadenosine pyrophosphate; D000246:Adenosine Diphosphate Ribose; D000245:Adenosine Diphosphate Glucose; D000249:Adenosine Monophosphate; D008345:Manganese; C011440:diadenosine triphosphate; C058796:ADP-ribose pyrophosphatase I; C058797:ADP-ribose pyrophosphatase II; D011755:Pyrophosphatases; D008274:Magnesium