Reactome: A Curated Pathway Database

Defective MMAA does not protect MUT (R-HSA-3322135)

Species Homo sapiens

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).

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Additional Information
Compartment mitochondrial matrix
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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]