Regulation of Escherichia coli formate hydrogenlyase activity by formate at alkaline pH.
Escherichia coli possesses two hydrogenases, Hyd-3 and Hyd-4. These, in conjunction with formate dehydrogenase H (Fdh-H), constitute distinct membrane-associated formate hydrogenlyases, FHL-1 and FHL-2, both catalyzing the decomposition of formate to H(2) and CO(2) during fermentative growth. FHL-1 is the major pathway at acidic pH whereas FHL-2 is proposed for slightly alkaline pH. In this study, regulation of activity of these pathways by formate has been investigated. In cells grown under fermentative conditions on glucose in the presence of 30 mM formate at pH 7.5, intracellular pH was decreased to 7.1, the activity of Fdh-H raised 3.5-fold, and the production of H(2) became mostly Hyd-3 dependent. These results suggest that at alkaline pH formate increases an activity of Fdh-H and of Hyd-3 both but not of Hyd-4.
Department of Biophysics, Biological Faculty, Yerevan State University, 1 Alex Manougian Str., 375049 Yerevan, Armenia.
Nelli
N
Mnatsakanyan
Anait
A
Vassilian
Liparit
L
Navasardyan
Karine
K
Bagramyan
Armen
A
Trchounian
D000255:Adenosine Triphosphate / Q000378:metabolism; D000468:Alkalies / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins; D005560:Formate Dehydrogenases / Q000378:metabolism*; D005561:Formates / Q000494:pharmacology*; D005786:Gene Expression Regulation; D006859:Hydrogen / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D006864:Hydrogenase / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism
D000468:Alkalies; D029968:Escherichia coli Proteins; D005561:Formates; D009097:Multienzyme Complexes; C030544:formic acid; D006859:Hydrogen; D000255:Adenosine Triphosphate; D006864:Hydrogenase; C455599:hydrogenase 4, E coli; D005560:Formate Dehydrogenases; C054017:formate hydrogenlyase; D011188:Potassium