02563nas a2200265   4500008004100000022001400041245011100055210006900166260007900235300001400314490000700328520157900335653002901914653001801943653002501961653002301986653002202009653002802031100001802059700002102077700001902098700003302117700001902150856012802169       2007                        eng d  a0141-022900aTryptophan residue is identified in the substrate binding of penicillin G acylase from Kluyvera citrophila0 aTryptophan residue is identified in the substrate binding of pen  a360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USAbELSEVIER SCIENCE INCcAPR  a1389-13970 v403 a<p>Penicillin acylases are important enzymes in pharmaceutical industry for the production of semi-synthetic beta-lactam antibiotics via the key intermediate 6-aminopenicillanic acid. The penicillin G acylase purified from Kluyvera citrophila (KcPGA) on modification with tryptophan-specific reagents such as N-bromo succinamide (NBS) and 2-hydroxy 5-nitrobenzylbromide (HNBB) showed partial loss of activity and substrate protection. Various solute quenchers and substrate were used to probe the microenvironment of the putative reactive tryptophan through fluorescence quenching. Homology modeling of KcPGA structure has been carried out. Docking substrate on this modeled KcPGA structure identifies the tryptophan residue that is directly influenced by substrate binding. To confirm the biological significance of this particular tryptophan, we did a sequence comparison of PGAs from various organisms. The sequence alignment clustered the matches into two sets, those closer to (&gt; 40% identical) KcPGA and had the tryptophan of interest present in them formed the first set, while those less identical (&lt; 30%) to KcPGA and the particular tryptophan absent in them formed the second set. It is clear from the reported kinetic parameters of representative members of these two sets that the affinity for penicillin G (penG) of the former class is several times better. Thus, based on our studies we suggest that the tryptophan residue in the identified position is important for binding substrate penG by the acylases. (c) 2006 Elsevier Inc. All rights reserved.</p>10afluorescence measurement10aK. citrophila10aPenicillin G acylase10asequence alignment10asubstrate-docking10atryptophan modification1 aKumar, Suresh1 aPrabhune, Asmita1 aPundle, A., V.1 aKarthikeyan, Muthukumarasamy1 aSuresh, C., G.  uhttps://library.ncl.res.in/content/tryptophan-residue-identified-substrate-binding-penicillin-g-acylase-kluyvera-citrophila01521nas a2200217   4500008004100000022001400041245008500055210006900140260011700209300001000326490000600336520066800342653004301010653001901053653002501072653003501097100001601132700001801148700002101166856011601187       2008                        eng d  a0973-626300aImmobilization of penicillin G acylase on amino functionalized mesoporous silica0 aImmobilization of penicillin G acylase on amino functionalized m  aSECTOR A-80, SCHEME NO 54, VIJAY NAGAR, A B ROAD, INDORE, 452 010 MP, INDIAbRESEARCH JOURNAL BIOTECHNOLOGYcNOV  a18-210 v33 a<p>Penicillin G acylase was immobilized on Amino functionalized mesoporous silica by adsorption method. In this paper we present the effect of penicillin G acylase immobilization on amino-functionalized mesoporous silica and the effect of silica as host matrix on enzyme kinetics. The loading capacity of immobilized Penicillin G acylase is 34 mg protein per 0.5 g of SBA-15. About 65% of the protein was adsorbed on mesoporous silica. The stability of penicillin acylase was enhanced after immobilization on mesoporous silica. The adsorbed enzyme is more stable than the soluble form, both to temperature and pH environments and retained 73% of its activity.</p>10aAmino functionalized mesoporous silica10aImmobilization10aPenicillin G acylase10apH and temperature stabilities1 aSridevi, N.1 aPallavi, Shah1 aAsmita, Prabhune  uhttps://library.ncl.res.in/content/immobilization-penicillin-g-acylase-amino-functionalized-mesoporous-silica-002419nas a2200229   4500008004100000022001400041245008800055210006900143260007300212300001200285490000800297520159300305653002501898653002701923653003401950653001101984100001801995700001602013700002102029700002002050856011902070       2008                        eng d  a1387-181100aStructural features of Penicillin acylase adsorption on APTES functionalized SBA-150 aStructural features of Penicillin acylase adsorption on APTES fu  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcDEC  a157-1650 v1163 a<p>The immobilization of Penicillin acylase (PGA) enzyme (which belongs to the Ntn hydrolase super family) into the amino-functionalized SBA-15 mesoporous molecular sieve is carried out to see the effect of silica as a host matrix on the enzyme kinetics. Physicochemical characterization by nitrogen adsorption, powder XRD and TEM methods indicate that the characteristic hexagonal features and the original pore structure of the parent SBA-15 is retained even after the incorporation of PGA. The adsorption of PGA on SBA15 shows a dependence on the pore volume and the composition of the adsorbent. The maximum loading of the enzyme was observed at pH 7.8, slightly below the isoelectric point of the enzyme. The loading capacity of immobilized PGA is 34 mg protein per 0.5 g of SBA-15. The trapped enzyme is more stable than the soluble form to temperature and pH environments and retained 73% of its activity after immobilization. This enhanced stability is attributed to the protective nature of the cage itself and to the rigidity of the SiO(2) matrix, which reduces the freedom of peptide-chain refolding of molecular motions that occur in denaturation processes. The strength of binding is very strong; however, the activity of the immobilized enzyme is then simply restored with very little leakage of enzyme from the support. An important feature of the immobilized PGA enzyme is the excellent reusability without significant loss in activity, which indicates potentially exciting industrial/biomedical application of this support. (C) 2008 Elsevier Inc. All rights reserved.</p>10aPenicillin G acylase10aPGA immobilized SBA-1510apH and temperatures stability10aSBA-151 aShah, Pallavi1 aSridevi, N.1 aPrabhune, Asmita1 aRamaswamy, Veda  uhttps://library.ncl.res.in/content/structural-features-penicillin-acylase-adsorption-aptes-functionalized-sba-15-002125nas a2200217   4500008004100000022001400041245010600055210006900161260007900230300001400309490000800323520130700331653002001638653001901658653002501677653002301702653001201725100002001737700001901757856013101776       2010                        eng d  a0273-228900aStudies of penicillin G acylase immobilization using highly porous cellulose-based polymeric membrane0 aStudies of penicillin G acylase immobilization using highly poro  a999 RIVERVIEW DRIVE SUITE 208, TOTOWA, NJ 07512 USAbHUMANA PRESS INCcFEB  a1130-11450 v1603 a<p>The different ionic molecules/compounds were used as a ligand for the immobilization of penicillin G acylase on the highly porous cellulose-based polymeric membrane having buffer flux 1,746 LMH (L m(-2) h(-1)) at 0.5 bar pressure. The immobilized enzyme activity around 250 U-App was obtained with the ligand such as proline, tryptophan, casein acid hydrolysate, and brilliant green. Comparatively, proline showed less IMY% (percentage immobilization yield-58) but higher RTA% (percentage of activity retention-71) and specific activity (145 U-App g(-1)). However, the crosslinked preparation of brilliant green obtained using glutaraldehyde showed 82 +/- 2.7% immobilized enzyme activity after the completion of successive five cycles. In comparison with the free enzyme, the enzyme immobilized on the brilliant green coupled membrane showed around 2.4-fold increase in K-m value (47.4 mM) as well as similar optimum pH (7.2) and temperature (40 degrees C). The immobilized enzyme retained almost 50% activity after 107 days and 50 cycles of operation. Almost 50% decrease in buffer flux after enzyme immobilization was observed. At the end of the 30 cycles, flux pattern shows around 38% decrease in buffer flux however, after 16 cycles of operation flux moves closer towards the steady state.</p>10aBrilliant green10aImmobilization10aPenicillin G acylase10aPolymeric membrane10aProline1 aAdikane, H., V.1 aThakar, D., M.  uhttps://library.ncl.res.in/content/studies-penicillin-g-acylase-immobilization-using-highly-porous-cellulose-based-polymeric-0