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Enzymatic Reaction Kinetics and Immobilization of Enzymes
Published in Debabrata Das, Soumya Pandit, Industrial Biotechnology, 2021
The three-dimensional configuration of the protein molecule is responsible for the formation of the active site which is in turn responsible for the specificity as well as the catalytic ability of the enzyme. Most enzymes require cofactors in order to make them active. A cofactor is a nonprotein compound which in combination with an inactive protein (known as apoenzyme) becomes a catalytically active protein (known as holoenzyme). Cofactors may be classified as shown in Figure 4.2.
Biomolecules
Published in Volodymyr Ivanov, Environmental Microbiology for Engineers, 2020
A coenzyme is a part of an enzyme that binds to a substrate molecule and is a part of the active center of the enzyme. Any changes in the structure of the active center caused by physical or chemical factors terminate enzymatic activity. Very often, the active center of an enzyme is a cofactor (coenzyme), which is a simple organic molecule able to attach to or detach from an enzyme molecule. Examples of these cofactors (coenzymes) are NAD+ and NADP+ (oxidized nicotinamide adenine dinucleotide and oxidized nicotinamide adenine dinucleotide phosphate), FMN (flavine mononucleotide), and FAD (flavin adenine dinucleotide), which play an important role in oxidation–reduction reactions.
Recent Advances in Artificial Cells With Emphasis on Biotechnological and Medical Approaches Based on Microencapsulation
Published in Max Donbrow, Microcapsules and Nanoparticles in Medicine and Pharmacy, 2020
Demonstration of the effectiveness of single enzyme systems led to research on artificial cells containing complex or multienzyme systems.39 Most enzymes in biological cells function as complex enzyme systems which also require cofactors. We first carried out basic studies to improve methods of preparing artificial cells containing complex enzyme system39 and also work out methods of retaining the required cofactors inside the cells for recycling. This can be done by binding the cofactor to a soluble polymer39 or by using a lipid-polymer artificial cell membrane so that the cofactors cannot diffuse out.39
The evaluation of the performance of rice husk and rice straw as potential matrix to obtain the best lipase immobilized system: creating wealth from wastes
Published in Preparative Biochemistry & Biotechnology, 2023
Mamta Kumari, Soham Chattopadhyay
Metal ions coordinate with central residues of active sites, changing enzymes’ affinity with substrates. They act as cofactors and enhance enzyme activity.[54] The figure shows a positive effect of all metal ions on lipase activity (Figure 5d). Among others, Mg2+ shows the highest impact, with a 2-fold increase in enzyme activity compared to no metals. A 2-fold increase in activity is observed for other metal ions, such as K+, Ca2+, and Cu2+. Other researchers also carried out a similar experiment with other lipases and reported the positive effect of the Mg2+ ion in the enzymatic hydrolysis of oil.[55]
Production of β-glucanase and protease from Bacillus velezensis strain isolated from the manure of piglets
Published in Preparative Biochemistry & Biotechnology, 2021
Anam Khalid, Miao Ye, Chunjie Wei, Binghong Dai, Ru Yang, Shoujun Huang, Zaigui Wang
In order to utilize β-glucanase effectively, the enzyme properties of β-glucanase were studied. The appropriate temperatures of β-glucanase reaction ranged from 60 °C to 70 °C, and reached the peak at 65 °C which was much higher than some other Bacillus sp.[43–45] The stability of β-glucanase was better at 55 °C, and more than 91.39% of β-glucanase activity retained until 4 hours. Which showed that the enzyme had a good stability. The optimum pH of enzymatic reaction was pH 6.0. β-glucanase activity was reduced 18.0% at pH 5.0 and 26.3% at pH 7.0. As for the pH stability, the enzyme activity was stable at the range 5.0 to 8.0, But the enzyme activity was not high, might be because of the influence of pH. The enzyme activity was most stable at pH 6.0. At pH 5.0, 7.0, and 8.0, the enzyme exhibited 96.5%, 86.8% and 82.2% residual activity. These results showed that the enzyme has the characteristic of alkali-resistance and acid-resistance, which means the strain, was suitable for animal intestinal environment.[46] Therefore, it is one possible application of β-glucanase from B. velezensis Y1 in animal breeding as an exogenous enzyme. The presence of K+ and Ca2+ enhanced the activity of β-glucanase. Zn2+ and Mg2+ have a slight inhibitory effect on enzyme activity while Al3+ and Cu2+ have a strong inhibitory effect on enzyme activity, which showed that role of the enzyme depends on the activation of metal ions. Gaur and Tiwari[47] reported that the enzyme activity of B. vallismortis increased significantly in the presence of Na+, Mg2+, and Ca2+. Some enzymes are not effective under normal conditions, and can only function with the participation of certain metal ions and cofactors. There are many mechanisms of metal ions acting on enzymes. Some metal ions participate in the catalytic reactions as active centers of enzymes, some connect enzymes and substrates as bridges, some neutralize charges and promote the binding of substrates to enzymes, and some stabilize the spatial conformation of enzymes after binding with them.[48,49] The decomposition capacities of β-glucanase to the substrates were different. The β-glucanase had the highest activity with CMC-Na, the enzyme activity was slightly decreased with microcrystalline cellulose, filter paper compared with the control, and the activities with cassava dregs, absorbent cotton and soybean meal were weak. These results indicated that the enzyme selectivity was toward cellulose substrate.