Distributive enzymes

As dehydrogenases (DH) are widely distributed enzymes, a number of studies have been carried out with these biocatalysts. For example, Willner el al. [20] have used a PQQ-monolayer functionalized gold electrode for the catalytic oxidation of NADH in the presence of Ca2+. In this scheme, the pyrrolo-quinoline quinine co-factor, PQQ, was covalently linked, as before for the GOx system [15, 20, 21], to the Au electrode,... 

Aminotransferases are widely distributed enzymes in nature, participating in a number of metabolic pathways (7-11). They catalyze the transfer of an amino group originating from an amino acid donor to a 2-ketoacid acceptor. In effect, this statement implies the reductive animation of a keto moiety, although a redox process is not directly involved. 

Peroxidases are widely distributed enzymes in the plant kingdom. Despite their ubiquity and the ever-increasing number of functions ascribed to them, the precise role and localization of the many isozymes remain uncertain... 

Diacylglycerol, on the other hand, is lipid soluble and remains in the lipid bilayer of the membrane. There it can activate protein kinase C (PKC), a very important and widely distributed enzyme which serves many systems through phosphorylation, including neurotransmitters (acetylcholine, a,- and P-adrenoceptors, serotonin), peptide hormones (insulin, epidermal growth hormone, somatomedin), and various cellular functions (glycogen metabolism, muscle activity, structural proteins, etc.), and also interacts with guanylate cyclase. In addition to diacylglycerol, another normal membrane lipid, phos-phatidylserine, is needed for activation of PKC. The DG-IP3 limbs of the pathway usually proceed simultaneously. 

Lysozyme (muramidase, mucopeptide JV-acetylmuramylhydrolase) is a widely distributed enzyme which lyses certain bacteria by hydrolysing the / (l-4)-linkage between muramic acid and N-acetylglucosamine of mucopolysaccharides of the bacterial cell wall. 

Roberts MS, Donaldson JD, Rowland M. Models of hepatic elimination a comparison of stochastic models to describe residence time distributions and to predict the influence of drug distribution, enzyme heterogeneity, and systemic recycling on hepatic elimination. J Pharmacokinet Biopharm 1988 16 41-83. 

In addition to serving as structural motifs, enols and enolates are involved in diverse biological processes. Several enol/enolate intermediates have been proposed to be involved in glycolysis (Section IV.A), wherein c/ -enediol 21 is proposed to be an intermediate in the catalytic mechanism of phosphohexose isomerase and an enol-containing enamine intermediate (22) has been proposed in the catalytic pathway of class I aldolase. In the case of glucose-fructose (aldose-ketose) isomerization, removal of the proton on Cl-OH produces the aldose while deprotonation of C2-OH yields the ketose, which is accompanied by protonation at the C2 and Cl positions, respectively. There are several cofactors that are involved in various biological reactions, such as NAD(H)/NADP(H) in redox reaction and coenzyme A in group transfer reactions. Pyridoxal phosphate (PLP, 23) is a widely distributed enzyme cofactor involved in the formation of a-keto acids, L/D-amino... 

An enzyme that catalyzes multiple rounds of elongation or digestion of a polymer while the polymer stays bound. A distributive enzyme, in contrast, releases its polymeric substrate between successive catalytic steps. 

Although aldose reductase is a widely distributed enzyme system, its general physiological role remains to be convincingly proven. Its only experimentally documented role is its participation in the generation of diabetic complications. 

A distributive enzyme, in contrast, releases its polymeric substrate between successive catalytic steps. 

FDA/PhRMA/Johris Hopkins University of various alleles with no or reduced en-educational workshop [64]. Because of 2yme activities for various metabolizing race/ethnic differences in the distribution enzymes [25-27], it is important to consid-... 

Superoxide dismutase (SOD) is a widely distributed enzyme that exists in a variety of forms. The copper-zinc enzyme (Cu,ZnSOD) is primarily located in the cytosol of eukaryotic cells. Mitochondria contain, in the matrix space, a distinctive cyanide-insensitive manganese-containing enzyme (MnSOD) similar to that found in prokaryotes. In addition, a ferrienzyme (FeSOD) has been identified in bacteria that is also insensitive to cyanide. Amino acid sequence homologies indicate two families of superoxide dismutases. One of these is composed of the Cu,ZnSODs and the other of MnSODs and FeSODs. All these superoxide dismutases catalyze the same reaction (2H -H O2 -h OJ H2O2 -t- O2) and with comparable efficiency. 

Enzyme-catalyzed biosynthesis of a biopolymer may proceed by either distributive polymerization or processive polymerization. In biosynthetic polymerizations, the enzyme that has added a monomeric unit to the growing chain can either dissociate or recombine randomly with other growing termini or it can remain bound to the same chain and increases the chain length by additional units. Enzymes that dissociate between each addition and distribute themselves among all the termini are called distributive. Enzymes that process along the same chain without dissociation are called processive. 

Enterokinase is found not only in the intestinal juice but is a very widely distributed enzyme which Delezenne has noted in the poison of serpents, in mushrooms, especially the Amanitas, and in bacteria. This investigator has found, in fact, that if pancreatic juice is inoculated with the res of Bacillus subtUis or BacUlus mesentericus, the liquid, after the bacteria have developed and when filtered, has acquired a pronounced proteolytic activity. Nevertheless, the bacterial culture, filtered before its mixture with the pancreatic juice, does not confer any activity on the latter. Finally, Hougardy has found that in milk there... 

Cyclic AMP. Among the many biochemical reactions of ATP is that of cyclisation to cyclic adenosine monophosphate, c-AMP, which is brought about by the widely distributed enzyme, adenyl cyclase. 

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