Formiminotransferase cyclodeaminase from porcine liver. An octomeric enzyme containing bifunctional polypeptides.
BIOCHIMICA ET BIOPHYSICA ACTA 1976;
453:151-61. [PMID:
999878 DOI:
10.1016/0005-2795(76)90259-2]
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Abstract
The forminiminotransferase-cyclodeaminase complex contains 2.8% carbohydrate and is composed of identical subunits based on molecular weight, isoelectric focusing and the number of CNBr-generated peptides. Electron microscopy demonstrated that the complex is a ring-shaped molecule when negatively stained both in solution and in crystalline structures. Rotational reinforcement of electron micrographs reveals that the molecule is composed of eight subunits arranged in a planar ring. These results indicate that each polypeptide of the complex must contain both enzymic activities.
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