Format

Send to

Choose Destination
Biochim Biophys Acta. 1976 Jul 15;436(4):800-10.

Membrane-associated reactions in ubiquinone biosynthesis in Escherichia coli. 3-Octaprenyl-4-hydroxybenzoate carboxy-lyase.

Abstract

A sensitive and quantitative assay for 3-octaprenyl-4-hydroxybenzoate carboxy-lyase has been developed. This enzyme, which catalyses the third reaction in ubiquinone biosynthesis in Escherichia coli, was partially purified and some of its properties determined. It was found that a considerable proportion of the carboxylyase activity could be separated from the membrane fraction in cell extracts prepared using a French press. Gel filtration showed the molecular weight of the enzyme to be about 340 000. For optimal activity the carboxy-lase was shown to require Mn2+, washed membranes or an extract of phospholipids, and an unidentified heat stable factor of molecular weight less than 10 000. The carboxy-lyase reaction was also shown to be strongly stimulated by dithiothreitol and methanol. The properties of the carboxy-lyase are compared with the three other enzymes concerned with ubiquinone biosynthesis in E. coli which have been studied in vitro. The fact that the substrate of the carboxy-lyase is membrane-bound and the enzyme is stimulated by phospholipid suggests that it normally functions in association with the cytoplasmic membrane in vivo.

PMID:
782527
DOI:
10.1016/0005-2736(76)90407-7
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center