Human phospholipid scramblase 1(hPLSCR1), when expressed in E. coli (BL-21 DE3), forms inclusion bodies that are functionally inactive. We studied the effects of various stress inducing agents and chaperones on soluble expression of hPLSCR1 in E. coli (BL-21 DE3). Addition of 3% (v/v) ethanol before induction and decreasing the post-induction temperature to 15A degrees C increased the solubility of hPLSCR1 to similar to 10 and similar to 15% respectively. Presence of groES-groEL complex solubilized the hPLSCR1 to similar to 30% of the total hPLSCR1. Absence of groES-groEL did not improve the solubility of hPLSCR1 suggesting that groES and groEL are the essential chaperones for the correct folding of hPLSCR1 when over-expressed in E. coli.similar to