Disulfide linked αoLH-gelonin conjugate failed to recombine with βoLH subunit to generate bioeffective hormonotoxin

Vinod Singh, Roy Curtiss

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Since, linking of ovine luteinizing hormone (oLH) to ribosome inactivating protein gelonin (in oLH-gelonin conjugate) occur via the alpha-subunit, αoLH, an attempt has been made to develop a 'universal' hormonotoxin for selective targeting to specific cells in the gonads. Four different molar ratios of oLH and N-succinimidyl-3-(2-pyridyldithio) propionate (SPDP) were used to activate the epsilon amino (ψ-NH2) groups of αoLH. The αoLH-SPDP derivatives recombine to native beta subunit of oLH (βoLH) and the purified recombinants retained substantial receptor binding, steroidogenic activity and immunoreactivity to native oLH. The disulfide linked αoLH-S-S-gelonin conjugates prepared by SPDP method were purified by gel filtration chromatography and analysed by reverse-phase high performance liquid chromatography (RP-HPLC). In order to obtain specificity and bioeffectivity, the αoLH-S-S-gelonin conjugates were allowed to recombine to native βoLH and the recombination mixture was further purified by gel-filtration chromatography. The RP-HPLC analysis of these recombinants indicated that αoLH-S-S-gelonin did not recombine to βoLH. The failure of recombination may be due to the reasons. (i) The site of ε-NH2 activation by SPDP may be different in the αoLH than the native oLH. (ii) The activation site may be in close proximity to the annealing site which facilitates the recombination of β-subunit but failured to reassociate to αoLH-S-S-gelonin conjugate. (iii) The introduction of gelonin (30 kDa basic protein) might have induced some steric hinderence for βoLH to recombine to the αoLH site which might have been masked in αoLH-S-S-gelonin conjugates. (Mol Cell Biochem 120: 95-102, 1993)

Original languageEnglish (US)
Pages (from-to)95-102
Number of pages8
JournalMolecular and Cellular Biochemistry
Volume120
Issue number2
DOIs
StatePublished - Mar 1 1993

Keywords

  • gonadotropin
  • immunoreactivity
  • receptor binding
  • steroidogenesis

ASJC Scopus subject areas

  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology

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