The NH2-terminal residues of rat liver proteasome (multicatalytic proteinase complex) subunits, C2, C3 and C8, are N alpha-acetylated

FEBS Lett. 1990 Apr 24;263(2):373-5. doi: 10.1016/0014-5793(90)81417-m.

Abstract

Rat liver proteasome (multicatalytic proteinase complex) is a 20S-ring shaped particle having a molecular mass of 750 kDa, and is composed of at least 13 non-identical components ranging from 21 to 31 kDa in size. We found here that the NH2-terminal residues of all the known 13 components, except for C5, are not reactive to phenylisothiocyanate. Among them, components C2, C3 and C8 are blocked in their NH2-termini with N alpha-acetyl-Met, N alpha-acetyl-Ala, and N alpha-acetyl-Ser, respectively. The NH2-terminal portions of C2, C3, and C8 exhibit sequence similarity to one another, but that of the non-blocked component C5 differs from those of C2, C3, and C8.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Amino Acid Sequence
  • Animals
  • Cysteine Endopeptidases / analysis*
  • Liver / enzymology*
  • Mass Spectrometry
  • Molecular Sequence Data
  • Multienzyme Complexes / analysis*
  • Peptide Fragments / analysis
  • Proteasome Endopeptidase Complex
  • Rats

Substances

  • Multienzyme Complexes
  • Peptide Fragments
  • Cysteine Endopeptidases
  • Proteasome Endopeptidase Complex