ON THE INTERFACIAL ACTIVATION OF CANDIDA-ANTARCTICA LIPASE-A AND LIPASE-B AS COMPARED WITH HUMICOLA-LANUGINOSA LIPASE

The interfacial activation of Candida antarctica lipase A (CALA) and B (CALB) has been investigated and compared with that of Humicola lanug inosa lipase (HLL). CALB displayed no interfacial activation towards p -nitrophenyl butyrate (PNPB) when exceeding the solubility limit of th e substrate. No activation was observed towards p-nitrophenyl acetate (PNPA) at the addition of sodium dodecyl sulfate (SDS) nor in the pres ence of a solid polystyrene surface. The catalytic action of CALB was very different from that of Humicola lanuginosa lipase, which showed a pronounced interfacial activation with the same substrates. The basis for the anomalous behaviour of CALB is proposed to be due to the abse nce of a lid that regulates the access to the active site. in contrast to CALB, CALA expressed interfacial activation, but the activation wa s not as prominent as for Humicola lanuginosa lipase (HLL). The struct ural basis for the activation of CALA is unknown.