@article { ISI:000258819000009, title = {Characterization of smallest active monomeric penicillin V acylase from new source: a yeast, rhodotorula aurantiaca (NCIM 3425)}, journal = {Process Biochemistry}, volume = {43}, number = {9}, year = {2008}, month = {SEP}, pages = {961-967}, publisher = {ELSEVIER SCI LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

An intracellular monomeric penicillin V acylase (PVA) of 36,000 Da exhibiting pI of 4.19, purified from newly identified yeast source, Rhodotorula aurantiaca (NCIM 3425). The enzyme was purified by hydrophobic interaction chromatography. The enzyme showed optimal activity at 45 degrees C and retained 80\% activity after incubation at 45 degrees C and pH 5.5 for I h. The enzyme showed maximum activity at pH 5.5 and was very stable between pH 5.5-6.5 with optimum stability at pH 6.0. It exhibited 50\% of its original activity after 30 min incubation at 60 degrees C. Enzyme hydrolyzed substrates with benzyl side chain but preferred penicillin V as primary substrate. N-terminally located serine supports the fact that it belongs to Ntn (N-terminal nucleophile)-hydrolase superfamily. The initial ten amino acid residues of R. aurantiaca PVA were identical to the initial sequence of NADH dehydrogenase (EC 1.6.99.3): however the enzyme lacks dehydrogenase activity. EGTA, EDTA, hexane and ethyl acetate stabilized the activity where as small chain alcohols inhibited it. 1,4-Dioxane, THF (tetrahydrofurane), phenol and benzyl alcohol severely inhibited enzyme activity while BME and DTT increased it. Tween 80 and Tween 20 highly enhanced the activity where as SIDS and Triton X-100 inhibited it. (C) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {Intracellular enzyme, N-terminal sequencing, Penicillin V acylase, Purification, Rhodotorula aurantiaca, Substrate specificity}, issn = {1359-5113}, doi = {10.1016/j.procbio.2008.04.024}, author = {Kumar, Atul and Prabhune, Asmita and Suresh, C. G. and Pundle, Archana} } @article { ISI:000292161300005, title = {Streptomyces nucleases}, journal = {Critical Reviews in Microbiology}, volume = {37}, number = {3}, year = {2011}, month = {AUG}, pages = {227-236}, publisher = {INFORMA HEALTHCARE}, address = {52 VANDERBILT AVE, NEW YORK, NY 10017 USA}, abstract = {

Streptomyces nucleases are widely distributed and multifunctional enzymes acting on both DNA and RNA. They occur extra as well as intracellularly and can be classified under sugar specific and sugar non-specific nucleases. Nucleases play different roles like analytical, biological, and nutritional. They are also used in programmed cell death. Although more than 20 nucleases are reported to date, very little information is available regarding their structure-function relationship, active site based sequence homology, and the probable mechanism of action. This review describes the history, occurrence, localization, production, purification, properties, and applications of Streptomyces nucleases.

}, keywords = {Applications, Endonuclease, extracellular, production, Purification, Substrate specificity}, issn = {1040-841X}, doi = {10.3109/1040841X.2011.562173}, author = {Joshi, Amruta Pramod and Deshmukh, Sumedha Sharad} } @article { ISI:000330603800038, title = {Leucaena sp recombinant cinnamyl alcohol dehydrogenase: purification and physicochemical characterization}, journal = {International Journal of Biological Macromolecules}, volume = {63}, year = {2014}, month = {FEB}, pages = {254-260}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Cinnamyl alcohol dehydrogenase is a broad substrate specificity enzyme catalyzing the final step in monolignol biosynthesis, leading to lignin formation in plants. Here, we report characterization of a recombinant CAD homologue (LICAD2) isolated from Leucaena leucocephala. LICAD2 is 80 kDa homodimer associated with non-covalent interactions, having substrate preference toward sinapaldehyde with K-cat/K-m of 11.6 x 10(6) (M-1 s(-1)), and a possible involvement of histidine at the active site. The enzyme remains stable up to 40 C, with the deactivation rate constant (K-d*) and half-life (t(1/2)) of 0.002 and 5 h, respectively. LICAD2 showed optimal activity at pH 6.5 and 9 for reduction and oxidation reactions, respectively, and was stable between pH 7 and 9, with the deactivation rate constant (K-d*) and half-life (t(1/2)) of 7.5 x 10(-4) and 15 h, respectively. It is a Zn-metalloenzyme with 4 Zn2+ per dimer, however, was inhibited in presence of externally supplemented Zn2+ ions. The enzyme was resistant to osmolytes, reducing agents and non-ionic detergents. (C) 2013 Elsevier B.V. All rights reserved.

}, keywords = {Cinnamyl alcohol dehydrogenase (CAD), Metalloenzyme, Substrate specificity}, issn = {0141-8130}, doi = {10.1016/j.ijbiomac.2013.09.005}, author = {Patel, Parth and Gupta, Neha and Gaikwad, Sushama M. and Agrawal, Dinesh C. and Khan, Bashir Mohammad} } @article {44647, title = {Dynamics of loops at the substrate entry channel determine the specificity of iridoid synthases}, journal = {Febs Letters}, volume = {592}, year = {2018}, month = {AUG}, pages = {2624-2635}, abstract = {

Iridoid synthases belong to the family of short-chain dehydrogenase reductase involved in the biosynthesis of iridoids. Despite having high sequence and structural homology with progesterone 5 beta- reductase, these enzymes exhibit differential substrate specificities. Previously, two loops. L1 and L2 at substrate-binding pocket, were suggested to be involved in generating substrate specificity. However, the structural basis of specificity determinants was elusive. Here, combining sequence and structural analysis, site-directed mutagenesis, and molecular dynamics simulations, we have shown that iridoid synthase contains two channels for substrate entry whose geometries are altered by L1-L2 dynamics, primarily orchestrated by interactions of residues Glu161 and Gly162 of L1 and Asn358 of L2. A complex interplay of these interactions confer the substrate specificity to the enzyme.

}, keywords = {iridoid synthase, iridoids, Molecular dynamics simulations, progesterone 5 beta-reductase, Substrate specificity}, issn = {1873-3468}, doi = {10.1002/1873-3468.13174}, author = {Sandholu, Anand S. and Mohole, Madhura and Duax, William L. and Thulasiram, Hirekodathakallu V. and Sengupta, Durba and Kulkarni, Kiran} }