Abstract The present invention relates to simple and cost effective process for production of pharmacopoeial grade Insulin Lispro. The precursor protein expressed as inclusion bodies during fermentation of recombinant bacterial cells was isolated, chemically treated, partially purified, refolded and enzymatically converted to Insulin Lispro in the chromatographic elute. Chromatographic purification and crystallization of product yields pharmacopoeial grade Insulin Lispro. The present invention also relates to the process of enzymatic conversion of purified Proinsulin Lispro wherein ratio of trypsin and Carboxypeptidase B to purified Proinsulin Lispro is 1:5000 to 1:20000 and 1:500 to 1:10000, respectively and wherein the process is carried out in chromatographic column elute.
