Mutations in theMMAAGene in Patients With thecblADisorder of Vitamin B₁₂Metabolism

Abstract

The original article to which this Erratum refers was published in Human Mutation 24:509–516

B12 Trafficking in Mammals: A Case for Coenzyme Escort Service

“…In addition, MeaB increases the k cat of the mutase 2-fold and, interestingly, the presence of nucleotides is without further effect on rate enhancement by MeaB. Although the concentration of AdoCbl is low in cbl A cell lines , AdoCbl synthesis in extracts from these cells is comparable to that in control cell lines . These results suggest that in addition to the mutase, MeaB interacts with adenosyltransferase and influences AdoCbl synthesis in mitochondria.…”

“…This activity is catalyzed by adenosyltransferase that converts cob(II)alamin or aquocobalamin in the presence of a reductant to AdoCbl. The human enzyme is trimeric and binds the various cobalamin derivatives with moderate affinity (∼2–8 µM) . Spectroscopic analyses have revealed an unusual coordination environment for the cofactor bound to the enzyme, which is “base-off” in both the substrate cob(II)alamin and product AdoCbl oxidation states .…”

“…The human enzyme is trimeric and binds the various cobalamin derivatives with moderate affinity (∼2–8 µM) . Spectroscopic analyses have revealed an unusual coordination environment for the cofactor bound to the enzyme, which is “base-off” in both the substrate cob(II)alamin and product AdoCbl oxidation states . In the presence of ATP, four-coordinate cob(II)alamin ( i.e.…”

Novel Coenzyme B12-dependent Interconversion of Isovaleryl-CoA and Pivalyl-CoA

“…In numerous bacterial genomes, MeaB-like proteins are found in the same operon as the mutases (40). Mutations in the MeaB ortholog in humans results in methylmalonic aciduria, an inborn error of metabolism (41,42), pointing to the important role of this auxiliary protein in maintaining MCM function.…”

Atypical methylmalonic aciduria: frequency of mutations in the methylmalonyl CoA epimerase gene (MCEE)

“…At least 178 mutations in the MUT gene on chromosome 6p21 have been identified in mut patients (Worgan et al, 2006;Lempp et al, 2007). Mutations in the MMAA gene on 4q31.1-31.2 and in the MMAB gene on chromosome 12q24 have been identified in patients with the cblA and cblB disorders respectively (Lerner-Ellis et al, 2004;Lerner-Ellis et al, 2006). However, a number of patients have been identified who excrete elevated levels of methylmalonic acid who could not be assigned to any complementation group.…”