In vitro enzymatic

Akagi T, Higashi M, Kaneko T et al (2005) In vitro enzymatic degradation of nanoparticles prepared from hydrophobically-modified poly (y-glutamic acid). Macromol Biosci 5 598-602... 

Adenosine triphosphate (ATP) is one of the most important cofactors involved in many of the synthetic reactions going on within the cell. Its recent large scale in vitro enzymatic synthesis from adenosine and acetylphosphate is of particular interest. Three enzymes immobilized in polyacrylamide gel were used adenosine kinase, adenylate kinase and acetate kinase (lip. ... 

Comparison of MMP selectivity profiles for BMS -275291 and earlier generation inhibitors as determined by in vitro enzymatic assays. BMS-275291 is a broad spectrum MMP inhibitor similar to marimastat. 

Among other in vitro enzymatic polymerizations that have been studied are the oxidative polymerizations of 2,6-disubstituted phenols to poly(p-phenylene oxide)s (Sec. 2-14b) catalyzed by horseradish peroxidase [Higashimura et al., 2000b] and the polymerization of P-cellobiosyl fluoride to cellulose catalyzed by cellulase [Kobayashi, 1999 Kobayashi et al., 2001],... 

In vitro enzymatic polymerizations have the potential for processes that are more regio-selective and stereoselective, proceed under more moderate conditions, and are more benign toward the environment than the traditional chemical processes. However, little of this potential has been realized. A major problem is that the reaction rates are slow compared to non-enzymatic processes. Enzymatic polymerizations are limited to moderate temperatures (often no higher than 50-75°C) because enzymes are denaturated and deactivated at higher temperatures. Also, the effective concentrations of enzymes in many systems are low because the enzymes are not soluble. Research efforts to address these factors include enzyme immobilization to increase enzyme stability and activity, solubilization of enzymes by association with a surfactant or covalent bonding with an appropriate compound, and genetic engineering of enzymes to tailor their catalytic activity to specific applications. 

It is stated that during an in vitro enzymatic reaction the concentration of the enzyme shall not change during the test, and that the substrate concentration exceeds the enzyme concentration in orders of magnitude in a first approximation the substrate concentration is practically constant, too. Both of these assumptions transform a reaction of 2" order into the much simpler reaction of 0 order. If the concentrations of enzyme and substrate are similar, we get a reaction of order. The reaction rate v for the association reaction... 

Some of recent papers by Ratner et al. [63, 64] revealed that there are significant differences in the surface chemistry of Biomer lots. The surface of some lots was dominated by poly(diisopropylaminoethyl methacrylate) (DPAEMA or DIPAM), a high molecular weight UV stabilizer, which was absent from some older lots [65]. Ratner et al. carried out comparative studies on in vitro enzymatic and oxidative degradation of two lots of Biomer, BSU 001 and BSP 067. Lot BSU 001 contains both DPAEMA and an antioxidant, Santowhite powder, while BSP 067 contains only the antioxidant. It was found that DPAEMA retarded the enzymatic degradation process, but accelerated oxidative degradation. 

An in vitro enzymatic synthesis of sucrose was carried out in 1944 (5). A successful chemical synthesis was performed by Lemieux and Huber (6) in 1953 from acetylated sugar precursors. However, the economics and chemical complexities of both processes make them unlikely sources of supply. 

FIGURE 8.13 Response-surface diagram for the time of 100% in vitro enzymatic disintegration of albumin microparticles prepared by variation of glutaraldehyde concentration and duration of cross-linking. (From Oner, L. and Groves, MJ. (1993b). J. Pharm. Pharmacol., 45, 866-870. With permission.)... 

A set of molecules that rank high after this process would be synthesized and subject to biological tests, i.e., in vitro enzymatic assay or binding affinity experiments, in order to confirm design rationales. Simultaneously, X-ray co-crystal structures of these ligands in complex with the target are to be determined to further corroborate modeling results. Positive results from such approaches are decisive for selection of next set of compounds for synthesis and the future directions of lead optimization. 

Pedersen, B. and Eggum, B.O. 1983. Prediction of protein digestibility by an in vitro enzymatic pH-stat procedure. Z. Tierphysio. Tierernachr. Fultermittelkd. 49 265-277. 

A significant number of tryptophan and tryptamine chemical syntheses are known this section describes their biological synthesis in vivo (whole cells), the in vitro enzymatically catalysed synthesis and synthesis through chemo-enzymatic approaches. 

Apartin, C. and Ronco, A. (2001) Evaluation of a p-Galactosidase in vitro enzymatic test specific for heavy metal toxicity, Environmental Toxicology 16, 117-120. 

Free fatty acids are elevated in the plasma of obese patients and are known to cause muscle and liver insulin resistance. The Wako HR series NEFA-HR(2) is an in vitro enzymatic colorimetric method assay for the quantitative determination of non-esterified fatty acids (NEFA) in serum. Perform the assay on serum collected from mice fasted for a period greater than 4 h, but less than 16 h. Perform the test on samples immediately after collection, without freezing. Also note that hemolysis in the serum samples may interfere with the assay. 

The initial, rather rapid increase in CER found in the second stage of two-phase batch cultivation was somewhat unexpected. We decided to compare this value to the initial rates of glucose and cellobiose formation in in vitro enzymatic hydrolysis experiments (Figs. 4 and 5). The enzyme loadings were chosen to represent the actual enzyme-to-substrate ratio relevant to the point of cellulose addition and the point of maximum CER. 

In Vitro Enzymatic Modification of Proteins Through Hydrolysis... 

Gana et al. developed and validated a reversed-phase high performance liquid chromatographic method for the kinetic investigation of the chemical and enzymatic hydrolysis of benazepril hydrochloride [37]. Kinetic studies on the acidic hydrolysis of benazepril hydrochloride were carried out in 0.1 M hydrochloric acid solution at 50, 53, 58 and 63°C. Benazepril hydrochloride appeared stable in pH 7.4 phosphate buffer at 37°C, and showed susceptibility to in vitro enzymatic hydrolysis with porcine liver esterase (PLE) in a pH 7.4 buffered solution at 37°C. 

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