Characterization of multiple fumarase proteins in Escherichia coli.
Two different types of fumarase were found in sonic extracts of Escherichia coli; one required Fe-S for the enzyme activity, and the other did not. When the cells were grown without aeration, the Fe-S-independent enzyme occupied over 80% of the overall fumarase activity. Highly purified Fe-S-independent enzyme was suggested to be composed of four subunits (Mr = 48 kDa) by SDS-polyacrylamide gel electrophoresis and gel filtration. Amino acid and N-terminal sequence analyses supported the possibility that the enzyme is a product of fumC gene (FUMC). In aerobically grown cells, however, the content of FUMC was low and the Fe-S-dependent fumarase occupied over 80% of the overall activity. The Fe-S-dependent enzyme appeared to be labile and the activity was rapidly lost during purification. Although the spontaneous inactivation was previously ascribed to thermal lability (S.A. Woods & J.R. Guest (1987) FEMS Microbiol. Lett. 48, 219), the activity could be restored by anaerobic incubation with ferrous ions and SH-compounds.
Yumoto
N
N
Department of Chemistry, Faculty of Science, Kyoto University, Japan.
Tokushige
M
M
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000693:Anaerobiosis; D001483:Base Sequence; D004926:Escherichia coli / Q000201:enzymology*; D005296:Ferrous Compounds / Q000378:metabolism; D005649:Fumarate Hydratase / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism
D000596:Amino Acids; D005296:Ferrous Compounds; D007527:Isoenzymes; D013438:Sulfhydryl Compounds; D005649:Fumarate Hydratase