Purification and partial characterization of serum monocytotropic factor, a platelet-derived cyclooxygenase-inducing polypeptide

Luisa Minghetti, Giovanna Bartolini, Marina Orlandi, Mariella Chiricolo, Federico Licastro, Claudio Franceschi, Vittorio Tomasi

Research output: Contribution to journalArticle

Abstract

It has previously been shown that a heat- and acid-stable component of human and animal sera was capable of stimulating prostanoid biosynthesis in human blood monocytes, very probably by a mechanism involving cyclooxygenase induction. Many physico-chemical characteristics of this factor are similar to those of identified platelet factors. Here we show that human platelets are a rich source of this factor (serum monocytotropic factor) and that results from experiments using arachidonic acid or thrombin as releasers are consistent with its presence in platelet membranes. Serum monocytotropic factor has been purified 1500-fold by three Chromatographic steps. Purification was more difficult when starting from platelet releasates or lysates. The purified serum monocytotropic factor had an apparent molecular mass of 70 000 as judged by Sephadex G-75 chromatography and by polyacrylamide gel electrophoresis; however, when subjected to HPLC on a gel permeation column in the presence of 6 M urea, one major peak corresponding to a relative molecular mass (Mr) of 30000-35000 was observed, which suggests a homodimeric structure. It is therefore very likely that human platelets store, in addition to the two well-identified polypeptide growth factors, platelet-derived growth factor and transforming growth factor-β, a third polypeptide capable of regulating prostanoid production in monocytes.

Original languageEnglish
Pages (from-to)315-322
Number of pages8
JournalBiochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism
Volume958
Issue number3
DOIs
Publication statusPublished - Feb 19 1988

Keywords

  • (Monocyte)
  • Cyclooxygenase induction
  • Polypeptide growth factor

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Endocrinology

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