Hydrolysis biochemical

Photometric measurements of colouring in the AChE-biotests after biochemical hydrolysis of acetylthiocholine may be made by using any... 

The rate of hydrolysis is influenced by pH, temperature and calcium concentration. Calcium shifts the chemical equilibrium of this reaction to the right as it bonds the orthophosphate ions formed. In addition to chemical hydrolysis, biochemical hydrolysis also takes place in waters, particularly in sewage with a dense biological population. A considerable part of polyphosphates in sewage fed into wastewater treatment plants is hydrolysed. The half-time of polyphosphates in surface waters is given in days and tens of days. 

Edsall, J. T. George Scatchard, John G. Kirkwood, and the electrical interactions of amino acids and proteins. Trends Biochem. Sci. 7 (1982) 414-416. Eigen, M. Proton transfer, acid-base catalysis, and enzymatic hydrolysis. Angew. Chem. Int. Ed. Engl. 3 (1964) 1-19. 

Many formally endergonic biochemical processes become exergomc when they are coupled mechanistically to the hydrolysis of ATP... 

Phosphodiesterase Inhibitors. Because of the complexity of the biochemical processes involved in cardiac muscle contraction, investigators have looked at these pathways for other means of dmg intervention for CHF. One of the areas of investigation involves increased cycHc adenosine monophosphate [60-92-4] (cAMP) through inhibition of phosphodiesterase [9025-82-5] (PDE). This class of compounds includes amrinone, considered beneficial for CHF because of positive inotropic and vasodilator activity. The mechanism of inotropic action involves the inhibition of PDE, which in turn inhibits the intracellular hydrolysis of cAMP (130). In cascade fashion, cAMP-catalyzed phosphorylation of sarcolemmal calcium-channels follows, activating the calcium pump (131). A series of synthetic moieties including the bipyridines, amrinone and milrinone, piroximone and enoximone, [77671-31-9], C22H22N2O2S, all of which have been shown to improve cardiac contractiUty in short-term studies, were developed (132,133). These dmgs... 

Increasingly, biochemical transformations are used to modify renewable resources into useful materials (see Microbial transformations). Fermentation (qv) to ethanol is the oldest of such conversions. Another example is the ceU-free enzyme catalyzed isomerization of glucose to fmctose for use as sweeteners (qv). The enzymatic hydrolysis of cellulose is a biochemical competitor for the acid catalyzed reaction. 

Citraconic anhydride [616-02-4] M 112.1, m 8-9°, b 47°/0.03mm, 213°/760mm, d4 1.245, ng 1.472. Possible contamination is from the acid formed by hydrolysis. If the IR has OH bands then reflux with AC2O for 30 min, evaporate then distil the residue in a vacuum otherwise distil in a vacuum. Store in a dry atmosphere. [Biochem J 191 269 1980.]... 

B30 611 1976 gave m 69-70°). Hydrolysis using an equivalent of base in methanol gave the desired glueoside. This is a non-ionie detergent for reeonstituting membrane proteins and has a critieal micelle concentration of 30 mM. [Shimamoto et al. J Biochem (Tokyo) 97 1807 I985 Saito and Tsuchiya Chem Pharm Bull Jpn 33... 

Chirazymes. These are commercially available enzymes e.g. lipases, esterases, that can be used for the preparation of a variety of optically active carboxylic acids, alcohols and amines. They can cause regio and stereospecific hydrolysis and do not require cofactors. Some can be used also for esterification or transesterification in neat organic solvents. The proteases, amidases and oxidases are obtained from bacteria or fungi, whereas esterases are from pig liver and thermophilic bacteria. For preparative work the enzymes are covalently bound to a carrier and do not therefore contaminate the reaction products. Chirazymes are available form Roche Molecular Biochemicals and are used without further purification. 

Carboxypeptidases are zinc-containing enzymes that catalyze the hydrolysis of polypeptides at the C-terminal peptide bond. The bovine enzyme form A is a monomeric protein comprising 307 amino acid residues. The structure was determined in the laboratory of William Lipscomb, Harvard University, in 1970 and later refined to 1.5 A resolution. Biochemical and x-ray studies have shown that the zinc atom is essential for catalysis by binding to the carbonyl oxygen of the substrate. This binding weakens the C =0 bond by... 

Wood preservatives appear not to affect emission of corrosive vapours from wood, suggesting that the hydrolysis of acetyl polysaccharides is chemical, not biochemical. Some copper-base preservatives can give enough leachable copper ions to cause galvanic corrosion of other metals, notably aluminium and steel. 

It is well known that the 1-phosphates of the ketoses, L-fuculose (51) and L-rhamnulose (52) have considerable biochemical interest. Their chemical synthesis has not been described as far as is known to the writer, but the rate of acid hydrolysis of L-fuculose 1-phosphate, obtained by enzymatic synthesis, has been determined by Heath and Ghalambor (20) and that of L-rhamnulose 1-phosphate by H. Sawada (48) and by Chiu and Feingold (II). They found that the rate of... 

Hen egg-white lysozyme catalyzes the hydrolysis of various oligosaccharides, especially those of bacterial cell walls. The elucidation of the X-ray structure of this enzyme by David Phillips and co-workers (Ref. 1) provided the first glimpse of the structure of an enzyme-active site. The determination of the structure of this enzyme with trisaccharide competitive inhibitors and biochemical studies led to a detailed model for lysozyme and its hexa N-acetyl glucoseamine (hexa-NAG) substrate (Fig. 6.1). These studies identified the C-O bond between the D and E residues of the substrate as the bond which is being specifically cleaved by the enzyme and located the residues Glu 37 and Asp 52 as the major catalytic residues. The initial structural studies led to various proposals of how catalysis might take place. Here we consider these proposals and show how to examine their validity by computer modeling approaches. 

ATP is a compound that provides energy for biochemical reactions in the body when it undergoes hydrolysis. For the hydrolysis of ATP at 37°C (normal body temperature)... 

Thiamine can be considered to be the product of the quatemization of 4-methyl-5-(2-hydroxymethyl)thiazole (5) by an active derivative of 4-amino-5-(hydroxymethyl)-2-methyl pyrimidine (4) (Scheme 2). In living cells, pyramine can be activated by conversion into the diphosphate 7, via monophosphate 6, and the substrate of the enzyme responsible for the quatemization is not the thiamine thiazole, but its phosphate 8. The product of the condensation, thiamine phosphate (9), is finally converted into diphosphate 2—the biochemically active derivative—by hydrolysis to free thiamine, followed by diphosphorylation, or more directly, in some cases. Enzymes are known for all of the steps depicted in Scheme 2, and adenosine triphosphate (ATP) is, as usual, the phosphate donor. 

Nicholls, D.G. (1974). The influence of respiration and ATP hydrolysis on the proton electrochemical gradient across the inner membrane of rat liver mitochondria as determined by ion distribution. Eur. J. Biochem. 50,305-315. 

The standard free energy of hydrolysis of a number of biochemically important phosphates is shown in Table 10-1. An estimate of the comparative tendency of each of the phosphate groups to transfer to a suitable acceptor may be obtained from the AG of hydrolysis at 37 °C. The value for the hydrolysis of the terminal... 

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