Insight into substituent effects in Cal-B catalyzed transesterification by combining experimental and theoretical approaches

Effect of organic solvent on enzymatic degradation of cyclic PBS-based polymers by lipase N435

Poly(butylene succinate-co-cyclohexane dimethanol succinate) (P(BS-co-CHDMS)) and poly(butylene succinate-co-butanediol cyclohexanedicarboxylic acid) (P(BS-co-BCHDA)) were catalytically degraded by Candida antarctica lipase Novozyme 435 (N435) in CHCl₃ and THF. The results indicated that the degradation rate was P(BS-co-CHDMS) > P(BS-co-BCHDA) > poly(butylene succinate) (PBS). The degradation rate of copolyesters was higher in CHCl₃ than in THF, the highest degradation rate of 67% being obtained for P(BS-co-CHDMS). Hence, the CHCl₃ solvent is more suitable for the enzyme-catalytic degradation of copolyesters, since the lipase can easier recognize the butylene succinate (BS-), (butanediol cyclohexanedicarboxylic acid) (BCA-), and (cyclohexane dimethanol succinate-type) (CMS-type) ester bonds in this solvent. Moreover, it can recognize the CMS-type ester bonds with a higher specificity than the (butanediol cyclohexanedicarboxylic acid type) (BCA-type) ester bonds. Molecular simulation results indicated that the structure of the lipase was stable in CHCl₃ and THF. However, CHCl₃ proved to be more suitable for a stable activity of the enzyme. The active pocket contains acyl-binding hydrophilic residues which are recognized by the substrate. The increase in the content of saturated cycles can increase the hydrophobicity of the substrate and thus, the amount of substrate bond to enzyme active site is increased, which facilitates the enzymatic degradation of copolyesters.

Significantly increased catalytic activity of Candida antarctica lipase B for the resolution of cis-(±)-dimethyl 1-acetylpiperidine-2,3-dicarboxylate

Structure-based semi-rational engineering approach was applied to alter the binding pocket and substrate channel for enhancing the activity of CALB towards moxifloxacin chiral intermediate.

Quantitative Structure Activity Relationship of Cinnamaldehyde Compounds against Wood-Decaying Fungi

Cinnamaldehyde, of the genius Cinnamomum, is a major constituent of the bark of the cinnamon tree and possesses broad-spectrum antimicrobial activity. In this study, we used best multiple linear regression (BMLR) to develop quantitative structure activity relationship (QSAR) models for cinnamaldehyde derivatives against wood-decaying fungi Trametes versicolor and Gloeophyllun trabeum. Based on the two optimal QSAR models, we then designed and synthesized two novel cinnamaldehyde compounds. The QSAR models exhibited good correlation coefficients: R²_Tv = 0.910 for Trametes versicolor and R²_Gt = 0.926 for Gloeophyllun trabeum. Small errors between the experimental and calculated values of two designed compounds indicated that these two QSAR models have strong predictability and stability.

Computational studies on nitramino derivatives of 1-amino-1,2-azaboriridine as high energetic material

DFT calculations performed on 1-amino-2,3,3-trinitramino-1,2-azaboriridine show it to be a potential high energetic material with detonation performance comparable to HMX.