We examined the influence of culture conditions on the production of the recombinant fused protein Kringle 1 (Streptokinase) (K1(SK)) expressed in E. coil under the control of the lpp-lac promoter. The growth and the protein production were severely inhibited at glucose concentrations higher than 5 g/L. The highest yield of K1(SK) from the soluble extract was obtained using synthetic medium. Concentrations of inducer between 0.1 and 1 mM of IPTG did not significantly affect the production level of K1(SK) or the final cell density. Under optimal conditions the K1(SK) protein was expressed in an intracellular soluble form at about 3-4% of the total cellular protein.