Human tissue factor contains thioester-linked palmitate and stearate on the cytoplasmic half-cystine

Biochemistry. 1988 Jun 14;27(12):4227-31. doi: 10.1021/bi00412a004.

Abstract

The state of the five half-cystine residues in human tissue factor (TF) has been characterized. The results indicate that the four half-cystines in the extracellular domain of TF form two disulfide bonds and the half-cystine in the cytoplasmic region is acylated by palmitic acid and stearic acid. The extracellular disulfide cross-links, Cys49-Cys57 and Cys186-Cys209, were deduced from the analysis of tryptic peptides. Acylation of the cytoplasmic half-cystine was demonstrated by purifying and characterizing fibroblast TF from cells labeled with [3H]palmitic acid. Radiolabeled fibroblast TF was observed by autoradiography following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The tritiated material covalently bound to the protein was identified as [3H]palmitate and [3H]stearate by reverse-phase high-pressure liquid chromatography. Deacylation of TF with hydroxylamine resulted in the spontaneous generation of disulfide-linked TF dimers. This result suggests that the disulfide-linked TF dimer, a minor component of most TF preparations, and the recently described heterodimeric form of TF are artifacts produced by deacylation of Cys245 and subsequent interchain disulfide bond formation.

Publication types

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

MeSH terms

  • Autoradiography
  • Chromatography, High Pressure Liquid
  • Cystine / analysis*
  • Cytoplasm / analysis
  • Humans
  • Immunochemistry
  • Palmitates / analysis*
  • Palmitic Acids / analysis*
  • Stearates / analysis*
  • Stearic Acids / analysis*
  • Thromboplastin / analysis*

Substances

  • Palmitates
  • Palmitic Acids
  • Stearates
  • Stearic Acids
  • Cystine
  • Thromboplastin