Gurrala Sheelu

Gelatin Blends with Alginate: Gels for Lipase Immobilization and Purification

Blends of natural polysaccharide sodium alginate (5%) with gelatin (3%) cross‐linked with glutaraldehyde provide beads with excellent compressive strength (8 × 104 Pa) and regular structure on treatment with calcium chloride. Lipases from porcine pancreas, Pseudomonas cepacia, and Candida rugosawere immobilized in such a blend with excellent efficiency. The immobilized enzymes were stable and were reused several times without significant loss of enzyme activity both in aqueous and reverse micellar media. The beads were functionalized with succinic anhydride to obtain beads with extra carboxylic acid groups. These functionalized beads were then successfully used for 7.4‐fold purification of crude porcine pancreatic lipase in a simple operation of protein binding at pH 5 and release at pH 8.5.

Design and synthesis of novel chrysene-linked pyrrolo[2,1-c] [1,4]-benzodiazepine hybrids as potential DNA-binding agents

Chrysene-linked pyrrolobenzodiazepine hybrids have been prepared that possess cytotoxicity in some cancer cell lines. They also exhibit promising DNA-binding affinity and this is supported by molecular modeling studies.

‘Gelozymes’ in organic synthesis: synthesis of enantiomerically pure (S)-2-hydroxy-(3-phenoxy)phenylacetonitrile with lipase immobilised in a gelatin matrix

Abstract Lipase from Pseudomonas cepacia (Amano PS and PS Lipase, Fluka) immobilised in microemulsion-based organogels formed by gelatin solubilisation and crosslinking with glutaraldehyde (‘Gelozyme’) has been used for the alcoholysis of the butanoate ester of racemic 2-hydroxy-(3-phenoxy)phenylacetonitrile with 1-butanol in hexane to obtain ( S )-2-hydroxy-(3-phenoxy)phenylacetonitrile. The immobilised enzyme can be used over 25 days (25 cycles) without significant loss of enzyme activity (

‘Gelozymes’ in organic synthesis. Part 2: Candida rugosa lipase mediated synthesis of enantiomerically pure (S)-cyano(3-phenoxyphenyl)methyl butyrate

Abstract Significant changes in enantioselectivity ( E ) have been observed when the butanoate ester of (±)-1-hydroxy-1-(3-phenoxyphenyl)acetonitrile was subjected to hydrolysis in acetate buffer (pH 4.5, E =6.4) and alcoholysis with 1-butanol in hexane catalysed by Candida rugosa lipase ( E =45). Enantiomerically pure ( S )-butanoate ester so obtained (e.e. 98.4%) was converted to the corresponding ( S )-cyanohydrin using Pseudomonas cepacia (Amano Ps) gelozyme. This strategy overcomes the problem of separation of the unwanted ( R )-ester from the ( S )-cyanohydrin.

Determination of enantiomeric excess of α-hydroxy-3-phenoxybenzeneacetonitrile and its n-butyl ester by chiral high-performance liquid chromatography

Determination of enantiomeric excess of alpha-hydroxy-3-phenoxybenzeneacetonitrile, an important intermediate in the production of several pyrethroid insecticides, is usually done after derivatization and gas chromatographic analysis on a beta-cyclodextrin-based column. In this communication we report a direct determination of enantiomeric excess of alpha-hydroxy-3-phenoxybenzeneacetonitrile and its n-butyl ester by chiral HPLC on Chiralcel OJ (Daicel, Japan) in a single run without derivatization.