Role of positive charge of lysine residue on ribosome-inactivating property of gelonin.
The report that gelonin cross-linked with monoclonal antibodies with the use of 2-iminothiolane (2-IT) exhibited higher cytotoxicity than the conjugates prepared with the use of N-succinimidyl-3-(2-pyridylthio) propionate (SPDP) alone, has prompted us to investigate the effect of epsilon-NH2 group modification with 2-IT on the ribosome-inactivating property (RIP) of gelonin. The purified gelonin was modified with 2-IT at a different molar ratio and their effects on immunoreactivity and ribosome-inactivating property were compared with those of N-succinimidyl 6-[3-(2-pyridyldithio) propionamido] hexanoate (long chain-SPDP) and SPDP modified gelonin derivatives. Modification of single amino group with 2-IT results in about 25-50% inhibition of immunoreactivity and 60-70% loss of protein synthesis inhibition activity. Modification of 2-3 amino groups further hampers both immunoreactivity and protein synthesis inhibition property of gelonin. Both the long chain-SPDP with SPDP modifications showed more pronounced effects on immunoreactivity and RIP activity as compared to the similar ratio of 2-IT modification(s). It may, therefore, be concluded that the positive charge plays an important role in the immunological as well as the protein synthesis inhibitory effect of gelonin.
Singh
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RC
Institute of Self-Organising Systems and Biophysics, Department of Biochemistry, North-Eastern Hill University, Shillong, Meghalaya, India.
Alam
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Singh
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D000941:Antigens / Q000276:immunology; D002474:Cell-Free System; D003432:Cross-Linking Reagents / Q000378:metabolism; D003851:Deoxyribonucleases / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D007096:Imidoesters / Q000378:metabolism; D008239:Lysine / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry* / Q000494:pharmacology*; D011500:Protein Synthesis Inhibitors / Q000737:chemistry* / Q000494:pharmacology*; D054789:Ribosome Inactivating Proteins, Type 1; D012270:Ribosomes / Q000187:drug effects*; D013388:Succinimides / Q000378:metabolism
D000941:Antigens; D003432:Cross-Linking Reagents; D007096:Imidoesters; D010940:Plant Proteins; D011500:Protein Synthesis Inhibitors; D054789:Ribosome Inactivating Proteins, Type 1; D013388:Succinimides; C085779:N-succinimidyl 6-(3-(2-pyridyldithio)propionamido)hexanoate; C005905:methyl 4-mercaptobutyrimidate; C025674:GEL protein, Gelonium multiflorum; D003851:Deoxyribonucleases; D008239:Lysine