The cSrc tyrosine kinase is a non-receptor tyrosine kinase protein that is encoded by the SRC gene. This gene is similar to the oncogene SRC gene of Rous sarcoma virus, encoding for vSrc. cSrc activation has been observed in about of 50 percent of tumors derived from the colon, liver, lung, breast, and pancreas. Screening small molecules that bind to cSrc is important in development of drug that inhibits the growth of the tumors. FLiK (Fluorescence Label in Kinase) method has been developed recently allowing to screening the binders that bind to in or outside ATP pocket of kinase. The cSrc kinase domain for FLiK was expressed in Escherichia coli, but the expression was unstable after keeping the strain in a fridge or deep freezer for a certain period. In this report, the authors presented the expression of cSrc kinase domain in Bacillus subtilis (B. subtilis) and purification using affinity chromatography. The expression of this protein was stable in B. subtilis using the strain recovered from a deep freezer. Purified kinase was then labelled by a fluorescence molecule, acrylodan. The molecular mass was identified by LC-ESI-MS (liquid chromatography electrospray ionization mass spectrometry). The labelled kinase exhibited the ability to use for screening its binders.