Open AccessEvaluation of the Protein Components of Citrate Lyase from Klebsiella aerogenes
Author(s) -
DIMROTH Peter,
EGGERER Hermann
Publication year - 1975
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1975.tb04061.x
Subject(s) - atp citrate lyase , enterobacter aerogenes , lyase , random hexamer , protein subunit , biochemistry , enzyme , cysteine , residue (chemistry) , acyl carrier protein , ultracentrifuge , homogeneous , chemistry , biology , citrate synthase , escherichia coli , biosynthesis , gene , physics , thermodynamics
1 The specific activity of homogeneous and fully active citrate lyase from Klebsiella aerogenes was found to be 55 U per mg protein. This corresponds to about 1.8 nmol enzyme ( M r ∼ 550000). 2 Based on these data and by use of several different methods it was found that about 4‐5 mol acyl carrier protein are present in the lyase. 3 Evidence is presented which excludes the participation of the cysteine residue, present in the acyl carrier protein, as an acyl‐carrying group. Thus, as in fatty acid synthetase, only the cysteamine residue of this subunit carries the acyl groups. 4 the composition of citrate lyase from three different proteins was confirmed. The molecular weights of these subunits are about 10000, 32000 and 54000; the latter molecular weight, which was questionable, was found to be 56000 by ultracentrifugation studies of the isolated, homogeneous protein. 5 The molar ratio of the three subunits mentioned in paragraph 4 was found to be about 1:1:0.8. This ratio indicates the presence of six copies of each of the three different subunits in the native enzyme complex, which probably consists of a hexamer.