Reactome: A Curated Pathway Database

Defective MMAA does not protect MUT

Stable Identifier
R-HSA-3322135
Type
Reaction [FailedReaction]
Species
Homo sapiens
Compartment
Locations in the PathwayBrowser
Summation

Methylmalonic aciduria type A protein (MMAA) is thought to act as a chaperone to MUT, the enzyme which utilises adenosylcobalamin (AdoCbl) as a cofactor. MMAA is suggested to play a dual role with regards to MUT protection and reactivation. Some AdoCbl-dependent enzymes undergo suicide inactivation after catalysis due to the oxidative inactivation of Cbl. MMAA is thought to play a protective role to prevent MUT being inactivated in this way. Defects in MMAA cause methylmalonic aciduria type cblA (cblA aka methylmalonic aciduria type A or vitamin B12-responsive methylmalonicaciduria of cblA complementation type; MIM:251100). Affected individuals accumulate methylmalonic acid in the blood and urine and are prone to potentially life threatening acidotic crises in infancy or early childhood. Mutations causing cblA include MMAA Q95*, R145*, Y207C and D87Ifs*11 (Dobson et al. 2002, Lerner-Ellis et al. 2004).

Literature References
Participants
Participant Of
Disease
Diseases
Name Identifier Synonyms
methylmalonic acidemia 14749 METHYLMALONICACIDURIA DUE TO METHYLMALONIC CoA MUTASE deficiency, METHYLMALONIC ACIDURIA, mut TYPE, METHYLMALONIC ACIDEMIA, cblB TYPE, methylmalonic aciduria mut type, METHYLMALONICACIDURIA, vitamin B12-RESPONSIVE, DUE TO DEFECT IN SYNTHESIS OF ADENOSYLCOBALAMIN--cbl B, methylmalonic aciduria cblB type, METHYLMALONIC ACIDURIA DUE TO METHYLMALONYL-CoA MUTASE DEFICIENCY, METHYLMALONIC ACIDURIA, VITAMIN B12-RESPONSIVE, DUE TO DEFECT IN SYNTHESIS OF ADENOSYLCOBALAMIN, cblA TYPE, methylmalonic aciduria, METHYLMALONIC ACIDURIA, VITAMIN B12-RESPONSIVE, DUE TO DEFECT IN SYNTHESIS OF ADENOSYLCOBALAMIN, cblB TYPE, METHYLMALONIC ACIDEMIA, cblA TYPE, METHYLMALONICACIDURIA, vitamin B12-RESPONSIVE, DUE TO DEFECT IN SYNTHESIS OF ADENOSYLCOBALAMIN--cbl A