Mechanism of 5-aminolevulinate synthase and the role of the protein environment in controlling the cofactor chemistry.
Article Details
- CitationCopy to clipboard
Ferreira GC, Zhang JS
Mechanism of 5-aminolevulinate synthase and the role of the protein environment in controlling the cofactor chemistry.
Cell Mol Biol (Noisy-le-grand). 2002 Dec;48(8):827-33.
- PubMed ID
- 12699240 [ View in PubMed]
- Abstract
5-Aminolevulinate synthase, a pyridoxal 5'-phosphate-dependent enzyme of the alpha-oxoamine synthase family, catalyzes the first step of the heme biosynthetic pathway in mammalian cells. This reaction entails the condensation of glycine with succinyl-coenzyme A to yield 5-aminolevulinate, carbon dioxide and CoA. Mutations in the erythroid aminolevulinate synthase gene lead to a defective enzyme and are associated with the erythropoietic disorder X-linked sideroblastic anemia. In the past few years, rapid scanning-stopped-flow spectroscopy and chemical quenched-flow studies of the ALAS reaction, under single- and multi-turnover conditions, have provided important results for the interpretation of the catalytic mechanism. In particular, the role of the protein scaffold in modulating the chemical reactivity of the pyridoxal 5'-phosphate cofactor and, thus, the catalytic pathway of ALAS has been investigated in our laboratory using transient kinetics and global analysis of the kinetic data.