Open AccessEvidence for the Existence of Two Interconvertible Forms of the Phosphofructokinase Dimer from Escherichia coli K‐12
Author(s) -
EWINGS Ken N.,
DOELLE Host W.
Publication year - 1976
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1976.tb10941.x
Subject(s) - phosphofructokinase , escherichia coli , enzyme , dimer , fractionation , chemistry , protein subunit , biochemistry , affinity chromatography , sepharose , fructose , gel permeation chromatography , chromatography , stereochemistry , glycolysis , organic chemistry , gene , polymer
The isolation by affinity chromatography of a low‐molecular‐weight form of phosphofructokinase from Escherichia coli K‐12 has resulted in an improved 2050‐fold purification. The enzyme was readily separable from the higher‐molecular‐weight form by Sepharose 6B fractionation. The enzyme was found to have a molecular weight of 65000 ± 6500 with a subunit molecular weight of 35000 ± 3500. The enzyme exists in either of two interconvertible forms dependent on the presence or absence of the positive of ectors ADP, fructose 6‐phosphate and ATP. A regulatory mechanism is postulated for this enzyme involving hysteric conformational changes; its importance in the mechanism of the Pasteur effect is discussed.