Reaction: Defective MMAB does not transfer adenosyl group from ATP to B12s
- in pathway: Defective MMAB causes MMA, cblB type
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).
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).
Reaction - small molecule participants:
cob(I)alamin [mitochondrial matrix]
ATP [mitochondrial matrix]
Reactome.org reaction link: R-HSA-3322125
======
Reaction input - small molecules:
cob(I)alamin(1-)
ATP(4-)
Reaction output - small molecules:
Reactome.org link: R-HSA-3322125