In vitro translation and processing of human hepatoma cell (Hep G2) γ-glutamyl transpeptidase Academic Article Article uri icon

Overview

MeSH Major

  • Carrier Proteins
  • Cell Membrane
  • Endoplasmic Reticulum
  • Mitochondrial Proteins
  • Saccharomyces cerevisiae Proteins
  • Sterols

abstract

  • Human hepatoma cell (Hep G2) gamma-glutamyl transpeptidase (gamma-GT), a 120 ka single-chain glycoprotein, is much larger than the expected precursor of the dimeric enzyme in other human tissues. However, the Hep G2 gamma-GT mRNA encodes a 63 kDa peptide, similar to that of rat gamma-GT mRNA product and to the predicted, unglycosylated precursor of the enzyme in human tissues. Translation in presence of dog pancreas microsomes results in processing of the 63 kDa to an 80 kDa core-glycosylated species which is subsequently cleaved to 58 and 22 kDa subunits resembling those in other human tissues. The unusually large Mr of gamma-GT in Hep G2 would thus seem to be due to further glycosylation and processing in the Golgi. A deficiency of the processing protease is the most likely reason for the persistence of the single-chain form of gamma-GT in Hep G2 cells.

publication date

  • August 15, 1988

Research

keywords

  • Academic Article

Identity

Digital Object Identifier (DOI)

  • 10.1016/0006-291X(88)90263-X

PubMed ID

  • 2900635

Additional Document Info

start page

  • 1167

end page

  • 73

volume

  • 154

number

  • 3