Active site geometry of porcine pancreatic lipase: an interesting switchover from Jones' to Seebach's model.

Porcine pancreatic lipase (PPL)-catalyzed hydrolysis of cis 3-acetoxyethyl-1,4-diphenyl and cis 3-acetoxyethyl-1-phenyl-4-(2-furyl) beta-lactams 1a and 1b proceeded with opposite stereoselectivity while the corresponding thienyl beta-lactam 1c showed no selectivity at all. An explanation based upon the dominance of hydrophobic and polar pockets in governing the stereoselectivity has been proposed.

DNA-cleavage studies on N-substituted monocyclic enediynes: enhancement of potency by incorporation of intercalating or electron poor aromatic ring and subsequent design of a novel phototriggerable acyclic enediyne.

A number of novel N-substituted enediynes (azaenediynes) 1-4 were synthesized as DNA cleaving agents. Enhancement of DNA cleavage potency was observed with those compounds which could interact with DNA through intercalation of the extended aromatic ring or through electrostatic attraction with electron poor aromatic ring. An acyclic enediyne 5 with a novel phototriggerable device was also synthesized and its DNA-cleaving activity was established.