Molecular and General Genetics MGG

, Volume 157, Issue 2, pp 155–165

Synthesis of the Escherichia coli K12 isoenzymes of ornithine transcarbamylase, performed in vitro

  • Michael L. Cleary
  • Robert T. Garvin
  • Eric James
Article

DOI: 10.1007/BF00267393

Cite this article as:
Cleary, M.L., Garvin, R.T. & James, E. Molec. Gen. Genet. (1977) 157: 155. doi:10.1007/BF00267393

Summary

The in vitro synthesis of enzymaticallyactive ornithine transcarbamylase (OTCase) directed by each of the E. coli K-12 OTCase genes (argF and argI) is described. The E. coli OTCase isoenzyme subunits are not identical, whether synthesized in vivo or in vitro, the argF-coded product being about 5% smaller. The OTCase protomers are enzymatically inactive but associate in vitro to an enzymatically active multimer. The rates of subunit association of argF and argI isoenzymes are considerably different. Utilizing the facile assay protocol presented, the regulation of in vitro OTCase synthesis by the specific holorepressor of the arginine regulon is demonstrated. Calculations based upon data presented indicate that there are about 65 molecules of argR gene product per bacterium, a substantially lower estimate than previously reported.

Copyright information

© Springer-Verlag 1977

Authors and Affiliations

  • Michael L. Cleary
    • 1
  • Robert T. Garvin
    • 1
  • Eric James
    • 1
  1. 1.Department of ChemistryUniversity of South CarolinaColumbiaUSA
  2. 2.Department of BiochemistryUniversity of Kentucky, College of MedicineLexingtonUSA
  3. 3.Department of MicrobiologySaint Louis University School of MedicineSt. LouisUSA
  4. 4.Department of BiochemistryUniversity of Kentucky, College of MedicineLexingtonUSA