@article { ISI:000239324300008, title = {Conformation and microenvironment of the active site of a low molecular weight 1,4-beta-D-glucan glucanohydrolase from an alkalothermophilic thermomonospora sp.: involvement of lysine and cysteine residues}, journal = {Biochemical and Biophysical Research Communications}, volume = {347}, number = {2}, year = {2006}, month = {AUG}, pages = {428-432}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, type = {Article}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

Conformation and microenvironment at the active site of 1,4-beta-D-glucan glucanohydrolase was probed with fluorescent chemo-affinity labeling using o-phthalaldehyde. OPTA has been known to form a fluorescent isoindole derivative by cross-linking the proximal thiol and amino groups of cysteine and lysine. Modification of lysine of the enzyme by TNBS and of cysteine residue by PHMB abolished the ability of the enzyme to form an isoindole derivative with OPTA. Kinetic analysis of the TNBS and PHMB-modified enzyme suggested the presence of essential lysine and cysteine residues, respectively, at the active site of the enzyme. The substrate protection of the enzyme with carboxymethylcellulose (CMC) confirmed the involvement of lysine and cysteine residues in the active site of the enzyme. Multiple sequence alignment of peptides obtained by tryptic digestion of the enzyme showed cysteine is one of the conserved amino acids corroborating the chemical modification studies. (c) 2006 Elsevier Inc. All rights reserved.

}, keywords = {1, 4-beta-D-glucan glucanohydrolase, active site microenvironment, Cysteine, lysine, OPTA, PHMB, Thermomonospora sp., TNBS}, issn = {0006-291X}, doi = {10.1016/j.bbrc.2006.06.100}, author = {Jagtap, Sharmili and Rao, Mala} } @article {Joshi, title = {Encapsulation of endoglucanase using a biopolymer Gum arabic for its controlled release}, journal = {Bioresource Technology}, volume = {98}, number = {2}, year = {2007}, month = {JAN}, pages = {368-372}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

{Gum Arabic, a biodegradable natural polymer was used as a matrix to encapsulate endoglucanase from Thermomonospora sp. The modified enzyme retained complete biocatalytic activity and exhibited a shift in the optimum temperature [

}, keywords = {Enzyme catalysis, OPTA, Thermomonospora sp., Xylanase}, issn = {1525-7797}, author = {Ramakrishnan, Anish and Pandit, Nilesh and Badgujar, Mahesh and Bhaskar, C. and Rao, Mala} } @article { ISI:000243366400007, title = {Glycine-assisted enhancement of 1,4-beta-D-xylan xylanohydrolase activity at alkaline pH with a pH optimum shift}, journal = {Biological Chemistry}, volume = {388}, number = {1}, year = {2007}, month = {JAN}, pages = {61-65}, publisher = {WALTER DE GRUYTER GMBH}, type = {Article}, address = {GENTHINER STRASSE 13, D-10785 BERLIN, GERMANY}, abstract = {

This is the first report describing the enhancement of xylanase activity by the neutral amino acid glycine. Xylanase activity is increased seven-fold at alkaline pH in the presence of glycine and its pH optimum is shifted from pH 7 to 8 without using any protein engineering techniques. Analysis of the steady-state kinetics revealed that glycine in the reaction mixture increases the K-m and k(cat) values of the enzyme. Chemoaffinity labeling and studies using glycine esters indicate an involvement of the carboxylate ion of glycine in enhancing xylanase catalytic activity. A novel possible mechanism for the glycine-assisted catalytic action of xylanase is proposed.

}, keywords = {Enzyme catalysis, OPTA, Thermomonospora sp., Xylanase}, issn = {1431-6730}, doi = {10.1515/BC.2007.007}, author = {Vathipadiekal, Vinod and Verma, Anamika and Rao, Mala} }