Biol. Pharm. Bull. 29(1) 38—42 (2006)

protein serine/threonine kinase (ROCK), is one of the central regulatory molecules for cytoskeleton control and cell adhesion process. ROCK also involves in other cell functions such as apoptosis and tumor invasiveness. Rho kinase is thought to play an important role in a variety of cellar functions such as stress fiber formation, focal adhesion formation, cell aggregation, cell morphology, cytokinesis, cell migration, and Ca -sensitization in the smooth muscle. Recent report showed that Rho kinase involves in regulation of the amyloid precursor protein processing. ROCK inhibitors are beneficial candidates for a wide range of diseases such as hypertension, inflammation, cancer, erectile dysfunction, and injury caused by ischemia and reperfusion. There are two types of ROCK: ROCK-I (ROCK-b) mainly found in hepatocytes, and ROCK-II (ROCK-a) in central nerve system (CNS). ROCK is activated by binding with the activated form of a low molecular weight G protein, Rho. Purified ROCK is important foundation for understanding the full function of ROCK, and is very useful in ROCK inhibitors screening. Katoh et al. have conformed that 1— 543 amino acid residua have catalytic function; further research suggested the kernel catalytic domain of ROCK (ROCK-CD) may be 92—354 amino acid residua. Turner et al. reported a way to harvest recombinant human ROCK-CD from Sf-21 cell, which became a main purified ROCK source currently. However, this procedure is timeconsuming and at a relatively high cost; which makes its price relatively expensive. It is needed to improve a procedure to harvest the ROCK-CD at low price, at high quality, and at large quantity; harvesting active ROCK-CD from Escherichia coli (E. coli) may be the choice met the request.