Compared to free enzymes in solution, immobilized enzymes are more robust and more resistant to environmental changes. More importantly, the heterogeneity of the immobilized enzyme systems allows an easy recovery of both enzymes and products, multiple re-use of enzymes, continuous operation of enzymatic processes, rapid termination of reactions, and greater variety of bioreactor designs. This paper is a review of the recent literatures on enzyme immobilization by various techniques, the need for immobilization and different applications in industry, covering the last two decades. The most recent papers, patents, and reviews on immobilization strategies and application are reviewed.

Preserving self-renewal, multipotent capacity, and large-scale expansion of highly functional progenitor cells, including endothelial progenitor cells (EPCs), is a controversial issue. These current limitations, therefore, raise the need of developing promising in vitro conditions for prolonged expansion of EPCs without loss of their stemness feature. In the current study, the possible role of three different natural extracellular substrates, including collagen, gelatin, and fibronectin, on multiple parameters of EPCs such as cell morphology, phenotype, clonogenic, and vasculogenic properties was scrutinized. Next, EPCs from GFP-positive mice were pre-expanded on each of these ECM substrates and then systemically transplanted into sublethaly irradiated mice to analyze the potency of these cells for marrow reconstitution. Our results revealed considerable promise for fibronectin for EPC expansion with maintenance of stemness characteristics, whereas gelatin and collagen matrices directed the cells toward a mature endothelial phenotype. Transplantation of EPCs pre-expanded on fibronectin resulted in widespread distribution and appropriate engraftment to various tissues with habitation in close association with the microvasculature. In addition, fibronectin pre-expanded cells were gradually enriched in the bone marrow after transplantation, resulting in marrow repopulation and hematologic recovery, leading to improved survival of recipient mice whereas gelatin- and collagen-expanded cells failed to reconstitute the bone marrow. This study demonstrated that, cell characteristics of in vitro expanded EPCs are determined by the subjacent matrix. Fibronectin-expanded EPCs are heralded as a source of great promise for bone marrow reconstitution and neo-angiogenesis in therapeutic bone marrow transplantation. J. Cell. Biochem. 117: 1934-1946, 2016. © 2016 Wiley Periodicals, Inc.

Immobilization of papain on Sepharose 6B in the presence of different concentrations of cysteine affected the enzyme activity depending on cysteine concentration. The maximum specific activity was observed when papain was immobilized with 200 mM cysteine. The immobilization process brought significant enhancement of stability to temperature and extreme pH values with respect to free papain. After immobilization, the optimum temperature of papain activity increased by 20 degrees C (from 60 to 80 degrees C) and its optimum pH activity shifted from 6.5 to 8.0. Catalytic efficiency (k(cat)/K(m)) and specific activity of the immobilized enzyme do not significantly change after immobilization. The temperature profile of this form of immobilized papain showed a broad range of activity compared with both free and immobilized form of papain in the absence of cysteine. This significant behavior in terms of activation energy is also discussed.

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During the holly month of Ramadan, Muslims fast every day from dawn to sunset. Although the effect of Ramadan fasting on general health has been widely studied, the impact of fasting on oral health and possible changes in salivary biochemicals, such as glucose, has not received much attentiom. The aim of our study was to evaluate the influence of fasting on the level of glucose in the saliva of healthy individuals. Salivary glucose was measured using an enzymatic method based on oxidation of glucose by glucoseoxidase followed by determination of resulting H2O2 in the presence of peroxidase. A reduction in mean concentration of glucose was observed in the saliva of all fasting subjects as compared to the control group. It was concluded that reduction in salivary glucose is mostly due to reduced food intake and may be beneficial to dental health

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Oral peroxidase, one of the most important salivary antioxidant enzymes, is subjected to alternation due to various body conditions. The aim of this study was to assess the effect of exercise intensity on salivary peroxidase activity. Using a randomized design, ten healthy male university students (mean age, 23.22; s (x) = 2.34 years) completed treadmill runs with initial velocity 6.73 km/h at the rate of 1.58 km/h increase every 3 min until exhaustion. Unstimulated whole saliva collected over a 5-min period in pre-weighed tubes before, immediately after exercise, and 1 h after exercise was analyzed for total protein and saliva peroxidase activity. The saliva flow rate ranged from 0.08 to 1.40 ml min(-1) at rest and was not significantly affected by the exercise. Peroxidase activity in each sample was measured using 4-amino antipyrine as substrate. In the incremental exhaustion run and also at 75% VO(2max), the secretion rates of peroxidase increased. No significant changes in saliva flow rate were observed in any treadmill run. Treadmill runs at 75% VO(2max) and to exhaustion increased the activity of peroxidase immediately after exercise which decreased after 1 h. It was concluded that short-duration, high-intensity exercise increases the activity rate of peroxidase despite no change in the saliva flow rate. These effects appear to be associated with changes in sympathetic activity and not the hypothalamic pituitary adrenal axis.