Current Biotechnology - Volume 4, Issue 2, 2015

Dihydrofolate reductase (DHFR) has emerged as a model enzyme to investigate the role of dynamics in catalysis. This review begins with a description of the timing of the protonation of the dihydrofolate substrate and the subsequent hydride transfer reaction. This is followed by a summary of the results obtained from bioinformatics, theoretical and experimental studies of coevolving DHFR residues. Some of these Read More

Lipase B from Candida antarctica (CaLB) is one of the most largely employed biocatalysts for the synthesis of chiral fine chemicals. The successful application of this enzyme has also been promoted by advanced computational methods able to simulate enantiodiscrimination at molecular and energy level. Quantitative prediction of enantioselectivity remains a challenging task, affordable by means of sophisticated and rigorous Read More

Oxidation reactions with oxygen and peroxides are difficult to control in the artificial environment of man-made chemistry. This makes oxizymes, i.e. oxidative enzymes that use oxygen or peroxide as co-substrates, very valuable targets for the chemical and pharmaceutical industries. Additionally, growing awareness of sustainability issues in society has encouraged the use of oxizymes in these industries. Some oxizym Read More

Hydroxynitrile lyase enzymes (HNLs) catalyze the stereoselective addition of HCN to carbonyl compounds to give valuable chiral hydroxynitriles. The discovery of new sources of HNL activity has been reported several times as the result of extensive screening of diverse plants for cyanogenic activity. Herein we report a two step-method that allows estimation of not only the native size of the active HNL enzyme but also its subs Read More

Thermotoga hypogea is a hyperthermophilic bacterium growing on carbohydrates and peptides, producing acetate, CO2 and H2 as major end products. Hydrogenase activity was detected in the cell-free extract of T. hypogea and a hydrogenase was purified to homogeneity. The purified enzyme was homotetrameric with a subunit of 65 kDa, and contained 16 atoms of Fe and 11.6 atoms of acid labile sulfur per mole subu Read More

The numerical imperative of random mutagenesis and high-throughput screening has created an overwhelming pressure for single measurements of enzyme activity as a preliminary diagnostic of functional improvement even if this leads on to a more traditionally thorough kinetic analysis of each potentially interesting mutant. This paper argues, with examples, that it is therefore all the more important to apply kinetic thinkin Read More

Electric eel acetylcholinesterase (AChE) was immobilised on electrospun nylon 6: chitosan nanofibres using glutaraldehyde (GA) cross-linking. The immobilisation protocol was optimised and a GA solution of 5% (v/v) resulted in the immobilisation of 0.334 mg/cm2 of AChE onto the nanofibres. The immobilised enzyme was characterised with respect to pH and temperature and results compared to the free enzyme. The Vmax v Read More

The Actinomadura R39 DD-peptidase is a very penicillin-sensitive enzyme. After a short time of contact with a liquid sample containing a beta-lactam antibiotic, the determination of the residual enzyme activity allows estimation of the concentration of the antibiotic in the sample. An alternative method utilizes the C-terminal domain of the Bacillus licheniformis penicillin sensor BlaR that is devoid of enzymatic activity. I Read More

Pleurotus ostreatus, using glucose as carbon source, is able to depolymerize a mixture of 2- naphthalene sulfonic acid polymers (NSAP), contained in a real petrochemical wastewater. On the contrary, its extracellular crude extracts, rich in laccases, are ineffective on NSAP degradation. Purified laccases and fungal extracellular extracts are able to depolymerize NSAP only in presence of specific synthetic or natural mediators. Wh Read More

In recent years a lot of attention has been paid to biofuel production and the transition from first to second generation feedstocks, mainly from the perspective of reducing the use of fossil resources and avoiding competition with the food chain. These lignocellulosic materials can be used for fermentative production of other biochemicals, building blocks or biomaterials, making them attractive for a biobased economy. The ma Read More

Despite the higher activity possessed by bacterial β-amylases, plant β-amylases are widely used for industrial processes. It is crucial that targeted improvements must be made on bacterial β-amylases for enhanced production, thermal and operational stability for their commercial viability. In this study, Bacillus polymyxa BWB-01 was cultivated in submerged fermentation and influence of cultivation conditions (pH, temperature Read More

Catechol-O-methyltransferase (COMT) catalyzes the transfer of a methyl group from Sadenosyl- L-methionine to catechols. Because COMT has an important role in the metabolism of catecholamines, catechol estrogens, and drugs with a catechol moiety such as L-Dopa, measurement of COMT activity in several tissues is important. Furthermore, COMT inhibitors are used clinically in the treatment of Parkinson’s disease, and activ Read More

Geobacillus kaustrophilus PW11, Geobacillus thermoleovorans PW13 and Geobacillus toebii PS4 were isolated form Tattapani hotspring of Himachal Pradesh, India and characterized for extracellular amylase activity. All the three Geobacillus spp. exhibited thermophilic amylase activity, which was predominantly extracellular. The activity was optimum at 90°C and pH 7.0. Interestingly, no amylase activity was observed at temperatu Read More