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Journal of Pharmaceutical and Biological Sciences

Site directed Pegylation: Role of pH and temperature, to increase the productivity of insulin oligomer conjugate

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Author Details: Ashutosh Sudhir Naik, Koduru Srivatsa, Krishnappa Mane, Phanichand Kodali, Laxmi Adhikary

Volume : 5

Issue : 4

Online ISSN : 2320-1924

Print ISSN :

Article First Page : 155

Article End Page : 160


An oral alternative to insulin has remained elusive for over ninety years and there are still multiple challenges to be addressed in this regard. Here in our work, we present a conjugation of an oral insulin precursor and an oligomer with increased binding affinity. During the conjugation of oral insulin precursor and oligomer the insulin oligomer conjugate is formed by the oligomer attaching to Amino group (NH3+) at €-carbon of lysine at B29 and free N-terminal of leader peptide followed by protease cleavage to remove the leader and linker peptide. To increase the binding affinity of oligomer towards Amino group (NH3+) at €-carbon of lysine at B29 the concentration of oligomer to precursor ratio is varied at different conditions like pH and temperature which yields 70% conversion to monoconjugated precursor and confirmed by protein mass fingerprinting in LC-MS. Due to high pKa value of lysine than glycine the affinity of oligomer shifts towards the Amino group (NH3+) at €-carbon at specific temperature and pH. This change in the conjugation reaction parameters is expected to be useful for later purification steps in the synthesis of an oral alternative for insulin.

Mono-conjugated Precursor, Oral-insulin precursor, Oligomer, €-carbon