Lipases are widely used as catalysts in industrial applications due to their thermostability and enantioselectivity. Candida antarctica lipase A (CAL-A) is highly thermostable in organic solvents and has therefore become a frequently used catalyst in chemical and pharmaceutical industry. CAL-A shows some unusual properties, which makes it a highly attractive enzyme. CAL-A is the only known lipase to have Sn2-preference towards triglycerides. It is able to hydrolyze sterically hindered alcohols, both secondary and tertiary alcohols. In addition, it shows a high chemoselectivity for the N-acylation of beta-amio esters, which makes CAL-A an important catalyst in the production of enantiopure amino acids. We have determined the crystal structure of CAL-A at 2.1 A resolution. CAL-A exhibits a typical alpha/beta hydrolase fold, consisting of a central beta-sheet and surrounding alpha-helices. The active site pocket is formed like a deep L-shaped tunnel covered by a lid that regulates the interfacial activation. Residues Ser184, Asp334 and His366 form the catalytic triad at the bottom of the pocket.
