Characterization of the enzyme complex involving the folate-requiring enzymes of de novo purine biosynthesis

Evidence is presented for a functional association of GAR TFase and the trifunctional protein within the protein complex consisting of GAR TFase, AICAR TFase, Ser HMase, and trifunctional protein. Resolution of the trifunctional protein from the remaining enzymes in the complex causes a loss of GAR...

Full description

Saved in:
Bibliographic Details
Published in:Biochemistry (Easton) 1980-09, Vol.19 (18), p.4313-4321
Main Authors: Smith, Gary K, Mueller, W. Thomas, Wasserman, Gail Folena, Taylor, William D, Benkovic, Stephen J
Format: Article
Language:English
Subjects:
Acyltransferases - isolation & purification
Acyltransferases - metabolism
Enzyme Activation
Folic Acid - pharmacology
Formates - isolation & purification
Formates - metabolism
Glycine - analogs & derivatives
Glycine - isolation & purification
Glycine - metabolism
Glycine Hydroxymethyltransferase - isolation & purification
Glycine Hydroxymethyltransferase - metabolism
Hydroxymethyl and Formyl Transferases
Kinetics
Multienzyme Complexes - isolation & purification
Multienzyme Complexes - metabolism
Phosphoribosylaminoimidazolecarboxamide Formyltransferase
Phosphoribosylglycinamide Formyltransferase
Purines - biosynthesis
Transferases - metabolism
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Evidence is presented for a functional association of GAR TFase and the trifunctional protein within the protein complex consisting of GAR TFase, AICAR TFase, Ser HMase, and trifunctional protein. Resolution of the trifunctional protein from the remaining enzymes in the complex causes a loss of GAR TFase activity which is regained upon recombination. The minimum stoichiometry for GAR TFase reactivation is 3:1 GAR TFase--trifunctional protein. Determination by ultracentrifugation of the sedimentation coefficient as a function of protein concentration disclosed that the complex is in mobile equilibrium with the individual proteins. However, mixed GAR TFase--trifunctional protein species can be detected by trapping with cleavable bifunctional cross-linking reagents. Additional support for their interaction is found in the kinetic coupling of the trifunctional protein and GAR TFase activities that leads to a fourfold more efficient formation of formylglycinamide ribotide commencing with formate rather than with 5,10-methenyl-H4folate triglutamate.
ISSN:0006-2960
1520-4995
DOI:10.1021/bi00559a026