Synthesis and enzymatic degradation of optically active L-lactide/1-methyltrimethylene carbonate copolymers

In this work, optical isomers of 1-methyltrimethylene carbonate (1 MTMC) we re synthesized from (R)-, (S)-, or (R, S)-1,3-butanediol and ethyl chlorofo rmate. These are abbreviated as R 1 MTMC. S 1 MTMC, and 1 MTMC, respectivel y. The cyclic carbonates and L-lactide (L-LA) were copolymerized using SmMe (C5Me5)(2)THF as initiator at 80 degreesC for 24 h in toluene. Thermal pro perties of the re suiting polymers indicated the copolymers containing L-LA more than 80 mol% to be crystalline polymers with melting temperatures (T- m). and ail the L-LA/1 MTMC copolymers to be random copolymers. Subsequentl y, we have examined the enzymatic degradation of these copolymers by choles terol esterase (from Pseudomonas sp.), lipoprotein lipase (from Pseudomonas sp.). and Proteinase K (from Tritirachium album). The cholesterol esterase and lipoprotein lipase degraded only poly (R 1 MTMC) and poly (1 MTMC), wh ile poly (S 1 MTMC) and all the copolymers were hardly degraded by these en zymes. Proteinase K could degrade relatively rapidly the copolymers with L- LA content more than ca. 60 mol%.