Protection and reactivation of human methylmalonyl-CoA mutase by MMAA protein.
Previous studies have reported that some adenosylcobalamin-dependent enzymes suffer inactivation during catalysis due to the oxidation of cobalamin. In addition, the protection or reactivation of their catalytic activities by proteins called "protectases" or reactivases is well known in bacteria. In this study, we examined the influence of human MMAA protein on the kinetics of the reaction catalyzed by methylmalonyl-CoA mutase (MCM) by testing both purified recombinant proteins in vitro. Our results showed that MMAA plays dual roles in MCM activity. When it was added at the beginning of the reaction, it prevents inactivation by guarding MCM. After 60 min of reaction, when MCM is inactive, the addition of MMAA increases the enzymatic activity through GTP hydrolysis, indicating reactivation of MCM by exchange of the damaged cofactor. Interaction between MCM and MMAA observed in vitro was confirmed in vivo by yeast two-hybrid system.
Departamento de Biología Molecular y Biotecnología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México, DF 04510, Mexico.
Tóshiko
T
Takahashi-Íñiguez
Humberto
H
García-Arellano
Mauricio A
MA
Trujillo-Roldán
María Elena
ME
Flores
D002384:Catalysis; D003001:Cloning, Molecular; D004789:Enzyme Activation; D006160:Guanosine Triphosphate / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D006868:Hydrolysis; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism; D008765:Methylmalonyl-CoA Mutase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000378:metabolism; D018832:Molecular Chaperones / Q000737:chemistry* / Q000378:metabolism; D020798:Two-Hybrid System Techniques
C497512:MMAA protein, human; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins; D018832:Molecular Chaperones; D006160:Guanosine Triphosphate; D008765:Methylmalonyl-CoA Mutase