02249nas a2200253 4500008004100000022001400041245019300055210006900248260007900317300001400396490000700410520123900417653001601656653002401672653003201696653001601728653002601744653001101770653001501781100001701796700002601813700002601839856013001865 2007 eng d a0141-022900aActive site directed chemical modification of alpha-galactosidase from bacillus stearothermophilus (NCIM 5146): involvement of lysine, tryptophan and carboxylate residues in catalytic site0 aActive site directed chemical modification of alphagalactosidase a360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USAbELSEVIER SCIENCE INCcAPR a1312-13200 v403 a

The catalytic amino acid residues of the extracellular a-galactosidase (alpha-D-galactoside galactohydrolase; EC 3.2.1.22) from Bacillus stearothermophilus NCIM 5146 were investigated by pH dependence and chemical modification studies. These results suggested that carboxylate and a lysine residue take part in catalysis and only lysine residues were essential for substrate binding. Carbodiimide mediated chemical modification of the enzyme also supported that a carboxylate residue located in the active site act as a nucleophile base in substrate cleavage. Acylation and reductive methylation of lysine residues by acetic, citraconic anhydride and sodium borohydride suggested that four protonated lysine residues carrying positive charge on its epsilon-amino group provides the positive charge density for binding of the substrate. Additionally four tryptophan residues also found near to the active site and in a moderately hydrophobic environment. Kinetic and thermal inactivation study of modified enzyme indicated that these tryptophan residues might have a role in the catalytic site as well as in the thermal stabilization of active site conformation at higher temperature. (c) 2006 Elsevier Inc. All rights reserved.

10aActive site10aalpha-galactosidase10aBacillus stearothermophilus10acarboxylate10aChemical modification10alysine10aTryptophan1 aGote, M., M.1 aKhan, Mohammad, Islam1 aKhire, Jayant, Malhar uhttps://library.ncl.res.in/content/active-site-directed-chemical-modification-alpha-galactosidase-bacillus-stearothermophilus02082nas a2200217 4500008004100000022001400041245012000055210006900175260007900244300001200323490000800335520125300343653001601596653002201612653001701634653002001651653002301671100001801694700002501712856012701737 2015 eng d a0273-228900aBiophysicochemical characterization of an alkaline protease from beauveria sp. MTCC 5184 with multiple applications0 aBiophysicochemical characterization of an alkaline protease from a999 RIVERVIEW DRIVE SUITE 208, TOTOWA, NJ 07512 USAbHUMANA PRESS INCcJAN a589-6020 v1753 a

This study illustrates the biophysicochemical properties of an alkaline protease, BAP (Beauveria sp. alkaline protease) from Beauveria sp. MTCC 5184. This protease exhibited maximum activity at 50 degrees C, pH 9.0, and stability in a broad pH range, in the presence of organic solvents, denaturants, as well as detergents. Wash performance studies revealed that BAP was able to remove blood clots/stains from blood-soaked cloth. Peptide mass fingerprinting results demonstrated partial homology of BAP with subtilisin-like proteinase. BAP showed catalytic activity against natural as well as synthetic substrates. Active site characterization of BAP confirmed the involvement of serine, tryptophan, and aspartic acid in catalytic activity. Detailed kinetic and thermodynamic studies of BAP demonstrated that the activation energy (Ea) for casein hydrolysis was 82.55 kJ/M, the specificity constant (Kcat/K-m), and the values of Delta G (change in Gibbs free energy) decreased with increase in temperature, whereas Delta H (change in enthalapy) and Delta S (change in entropy) were constant. The results of the present study indicate that BAP has potential for applications as detergent additive, in peptide synthesis, and in basic research.

10aActive site10aAlkaline Protease10aBeauveria sp10aOrganic solvent10aSubstrate kinetics1 aShankar, Shiv1 aLaxman, Ryali, Seeta uhttps://library.ncl.res.in/content/biophysicochemical-characterization-alkaline-protease-beauveria-sp-mtcc-5184-multiple-002635nas a2200229 4500008004100000022001400041245012200055210006900177260000800246300001100254490000900265520184800274653001602122653001802138653002802156653001102184653002702195100002202222700002202244700002002266856011902286 2020 eng d a0304-416500aMolecular determinant for specificity: differential interaction of alpha-amylases with their proteinaceous inhibitors0 aMolecular determinant for specificity differential interaction o cDEC a1297030 v18643 a

Background: alpha-Amylase inhibitors (alpha-AIs) belong to the discrete classes, and exhibited differential specificities against alpha-amylases from various sources. Several alpha-amylases and their complexes with inhibitors at the molecular level have been studied in detail. Interestingly, some alpha-AIs depict specific and selective interactions amid different insect alpha-amylases. Scope of review: There are studies to understand evolutionary variability and functional differentiation of insect alpha-amylases and their cognate inhibitors. We have examined sequence, structural, and interaction diversity between various alpha-amylases and alpha-AIs. Based on these analyses, we are providing a potential basis for the functional differentiation among certain insect a-amylases concerning mammalian counterparts and their interactions with different proteinaceous alpha-AIs. Major conclusions: Insect alpha-amylases have conserved domain architecture with differences in length, number of disulfide bonds, and secondary structure. Furthermore, few of them exhibit variable characteristics like chloride dependent activity, the presence of N-terminal glutamine residue to protect against proteolytic degradation, and loop variations near the enzyme active site. Conformation of alpha-AI protein could be an essential factor for their specificity and binding affinities towards target alpha-amylase(s). Furthermore, variation into the enzyme binding pocket residues might contribute to differential interactions with inhibitors. General significance: Molecular insights in the interactions between insect alpha-amylases and plant alpha-AI will provide the details of mechanisms assisting the inhibitor specificity. Furthermore, this information will help to design potent and effective alpha-AIs against specific alpha-amylase.

10aActive site10aalpha-amylase10aalpha-amylase inhibitor10aInsect10amolecular interactions1 aRane, Ashwini, S.1 aJoshi, Rakesh, S.1 aGiri, Ashok, P. uhttps://library.ncl.res.in/content/molecular-determinant-specificity-differential-interaction-alpha-amylases-their