Defective MMAB does not transfer adenosyl group from ATP to B12s

Stable Identifier
R-HSA-3322125
Type
Reaction [transition]
Species
Homo sapiens
Compartment
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Mitochondrial cob(I)yrinic acid a,c-diamide adenosyltransferase (MMAB) is an enzyme involved in the adenosylation of cobalamin. MMAB transfers an adenosyl group from ATP to cob(I)alamin (B12s) to form adenosylcabalamin (AdoCbl) (Fan & Bobik 2008, Leal et al. 2003).

Defects in MMAB cause methylmalonic aciduria type cblB (cblB aka methylmalonic aciduria type B or vitamin B12-responsive methylmalonicaciduria of cblB complementation type; MIM:251110). Affected individuals have methylmalonic aciduria and episodes of metabolic ketoacidosis, despite a functional methylmalonyl CoA mutase. In severe cases, newborns become severely acidotic and may die if acidosis is not treated promptly (Dobson et al. 2002). The point mutations R186W, R191W and E193K result in very low levels of AdoCbl (Dobson et al. 2002).

Literature References
PubMed ID Title Journal Year
18251506 Functional characterization and mutation analysis of human ATP:Cob(I)alamin adenosyltransferase

Fan, C, Bobik, TA

Biochemistry 2008
12438653 Identification of the gene responsible for the cblA complementation group of vitamin B12-responsive methylmalonic acidemia based on analysis of prokaryotic gene arrangements

Dobson, CM, Wai, T, Leclerc, D, Wilson, A, Wu, X, Doré, C, Hudson, T, Rosenblatt, DS, Gravel, RA

Proc. Natl. Acad. Sci. U.S.A. 2002
12514191 Identification of the human and bovine ATP:Cob(I)alamin adenosyltransferase cDNAs based on complementation of a bacterial mutant

Leal, NA, Park, SD, Kima, PE, Bobik, TA

J. Biol. Chem. 2003
Participants
Participant Of
Catalyst Activity
Catalyst Activity
Title
cob(I)yrinic acid a,c-diamide adenosyltransferase activity of MMAB mutants [mitochondrial matrix]
Physical Entity
Activity
Normal reaction
Disease
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
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