Hormonotoxins: the role of positive charge of lysine residue on the immunological, biological and cytotoxic properties of ovine lutropin-S-S-gelonin conjugates

Vinod Singh, Roy Curtiss

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Since the positive charge on the lysine residues plays an important role in the receptor recognition ability of oLH, the hormonotoxin has been synthesised with the use of 2-iminothiolane HC1 (2IT) and N-Succinimidyl-3-(2-pyridyldithio)-propionate (SPDP). The oLH activated with 2IT (oLH-10) was then mixed with SPDP activated gelonin (gelonin-30) in order to obtain a oLH-S-S-gelonin hormonotoxin. The conjugation mixture containing hormonotoxin was purified by gel-filtration chromatography according to the molecular weight and a complete physico-chemical, immunochemical and biochemical analysis were performed. The linkage occured through the ε-NH2 groups of α-subunit of oLH as judged from RP-HPLC analysis. A 1:1 (oLH:gelonin) molar ratio was obtained when determined with the use of several techniques. The hormonotoxins retained substantial receptor binding, steroidogenic activity and immunoreactivity. The competitive displacement analysis indicate that the binding occurs via the hormone part leaving the gelonin free which was probed with the gelonin antibodies. The presently described (C150A-02, C160A-02 and C170A-02) hormonotoxins exhibited higher receptor binding and toxicity to the target cells than the hormonotoxins prepared with the use of SPDP only. Therefore it is concluded that higher receptor binding and cytotoxicity may be due to the retention of positive charge on the lysine residues of oLH which was preserved during the conjugation process.

Original languageEnglish (US)
Pages (from-to)91-101
Number of pages11
JournalMolecular and Cellular Biochemistry
Volume130
Issue number1
DOIs
StatePublished - Jan 1994

Keywords

  • cytotoxicity
  • gelonin
  • gonadotropin
  • immunoreactivity
  • protein synthesis
  • receptor binding
  • steroidogenesis

ASJC Scopus subject areas

  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology

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