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|Title:||Significance of charge on lysine residue of ovine luteinizing hormone on immunological and biological properties of the hormone|
Singh, Ranjit C
Dubey, Rajesh K
|Abstract:||In order to understand the significance of positive charge of lysine residues of ovine luteinizing hormone (oLH) on immunological and biological activity, the ε-NH2 group(s) of ovine LH were sequentially modified with 2-iminthiolane (2IT) that preserves the positive charge of the lysine while the overall charge of the hormone remains unchanged. These studies have also been compared with the oLH modified by N-succinimidyl 3-(2 pyridyldithio) propionate (SPDP) and succinimidyl 6-[3-(2-pyridyldithio)propionamido] hexanoate (LC-SPDP) that abolish positive charge of lysine residues. The modification primarily occurs in the α-subunit. Sequential modification led to progressive reduction in receptor binding and immunological activities. However, the steroidogenic activity was substantially retained. The immunoreactivity and receptor binding properties of 2IT modified oLH (oLH-2 IT) were less affected when compared to SPDP (oLH-SPDP) or LC-SPDP (oLH-LC-SPDP) modified derivatives suggesting that increase in hydrophobic carbon chain in oLH -LC-SPDP molecule resulted in drastic inhibition in immunological and biological properties. But the steroidogenic potentia1 of oLH -2IT, oLH- LC- SPDP or oLH-SPDP was relatively comparable. This suggests that a single -NH2 group modification with 2IT would generate the site in the hormone for conjugation to the toxin/carrier proteins that may retain better immunological and biological activity compared to that of SPDP or LC-SPDP modified oLH.|
|ISSN:||0975-0959 (Online); 0301-1208 (Print)|
|Appears in Collections:||IJBB Vol.36(6) [December 1999]|
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