Open AccessFructose‐1,6‐bisphosphate‐activated pyruvate kinase from Escherichia coli
Author(s) -
SPERANZA Maria L.,
VALENTINI Giovanna,
MALCOVATI Massimo
Publication year - 1990
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1990.tb19178.x
Subject(s) - fructose 2,6 bisphosphate , fructose , phosphoenolpyruvate carboxykinase , allosteric regulation , chemistry , pyruvate kinase , formamide , fructose 1,6 bisphosphatase , escherichia coli , biochemistry , stereochemistry , enzyme , glycolysis , phosphofructokinase , organic chemistry , gene
The allosteric properties of the fructose‐1,6‐bis‐phosphate‐activated pyruvate kinase from Escherichia coli were examined in the presence of a number of fructose bisphosphate analogues, as well as of increased ionic strength (NaCl) and of the hydrogen‐bond‐breaking agent, formamide. Fructose 2,6‐bisphosphate, ribulose 1,5‐bisphosphate and 5‐phosphorylribose 1‐pyrophosphate gave allosteric activation (additive to that of fructose 1,6‐bisphosphate). Formamide always decreased V max , but left unchanged the K m for phosphoenopyruvate, while it decreased the concentration of fructose bisphosphate required to give half‐maximal activity ( K 0.5 ). NaCl increased the K 0.5 for both phosphoenolpyruvate and fructose bisphosphate, leaving V max unchanged. These results are consistent with ionic binding of fructose bisphosphate through phosphates and with a critical role of hydrogen bonds in stabilizing both the inactive and the active enzyme conformers.