Dineshkumar.P.
Micro therapeutic Research Lab, India
Title: Catalytic activity of N-terminal Methionine modification in recombinant Streptokinase expressed in E.Coli
Biography
Biography: Dineshkumar.P.
Abstract
Native streptokinase is usually prepared from culture of Streptococcus equisimilisfor therapeutic purpose of intravenous thrombolytic agent for the treatment of myocardial infarction. The N-terminal amino acid of native streptokinase starts with Isoleucine (I), Alanine (A), Glycine (G) and followed by Proline (P) etc. The first of amino acid of Isoleucine is playing an important role for the catalytic activity of streptokinase is binding towards inactive plasminogen to activate plasminogen. The specific activity of native streptokinase is 100000 IU/mg with the initial N- terminal isoleucine amino acid. Despite the recombinant streptokinase of N-terminal amino acid begins with methionine and it is a proteinogenic for E.Coli expression. Comparison for specific activity of recombinant streptokinase shows only 85000IU/mg than 100000IU/mg native streptokinase. The reason behind this objective is that there are two forms (Isomers) of streptokinase are expressed in E.Coli which was analysed by RP-HPLC and chromogenic assay. We have found that this variation is formed by isomer-1 has 85% of Streptokinase expressed without methionine (85000IU/mg) and Isomer-2 has 15% of streptokinase expressed with methionine (nil activity) in E.Coli. This Phenomena is clearly demonstrating that the presence and absence of methionine in isomers are varying the streptokinase activity. Hence the methionine alters the streptokinase catalytic activity and is an important role for both activity and immunogenic. This is the first attempt to explore the methionine variation by our method development on RP-HPLC and chromogenic assay for improving the suppression of risk management of myocardial infarction.