ATP-dependent conjugation of reticulocyte proteins with the polypeptide required for protein degradation

Proc Natl Acad Sci U S A. 1980 Mar;77(3):1365-8. doi: 10.1073/pnas.77.3.1365.


The heat-stable polypeptide (APF-1) required for ATP-dependent proteolysis in reticulocytes enters into high molecular weight conjugates upon incubation with the fraction of reticulocytes that is retained by DEAE-cellulose. Conjugate formation requires ATP and Mg2+ and its inhibited by N-ethylmaleimide. UTP and GTP are inactive. These properties are identical to those of ATP-dependent protein breakdown in the same system, suggesting that the conjugates are intermediates in this process. The APF-1 conjugates are stable in sodium dodecyl sulfate/polyacrylamide gel electrophoresis and Sephadex G-75 isolation and are resistant to mild acid, alkali, heat denaturation, and reduction; the conjugates are therefore covalent.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / metabolism*
  • Animals
  • Edetic Acid / pharmacology
  • Ethylmaleimide / pharmacology
  • Hydrogen-Ion Concentration
  • Kinetics
  • Peptide Hydrolases / metabolism*
  • Protein Binding / drug effects
  • Proteins / metabolism*
  • Rabbits
  • Reticulocytes / metabolism
  • Ribonucleotides / pharmacology


  • Proteins
  • Ribonucleotides
  • Adenosine Triphosphate
  • Edetic Acid
  • Peptide Hydrolases
  • Ethylmaleimide