Dehydrogenases alanine dehydrogenase

Bacterial membranes contain respiratory enzymes resembling those found in inner mitochondrial membrane (Haddock and Jones, 1977), which oxidize NADH to NAD+ and H20. C.freundi grown aerobically, possess a particularly active membrane-bound NADH-oxidase activity (1.0—1.5 pmol/min-mg of protein at 30°C. Since these membranes alone or in the presence of NAD+ do not oxidize substrates such as L-alanine, L-lactate, or ethanol, they act as indicators of the activity of lactate dehydrogenase, alanine dehydrogenase, or alcohol dehydrogenase ... 

The feasibility of such reactor has been demonstrated by the production of alanine from lactic acid. The unfavorable equilibrium in this lactate dehydrogenase-alanine dehydrogenase reactor is offset by using a high concentration of substrate and by the rapid consumption of pyruvic acid by the second enzyme. It is worthy of mention that such a system also serves as a model for potential therapeutic applications whereby enzymes and... 

In preceding sections of this chapter, the important metabolic reactions which yield ammonia have been discussed. Certain of these systems are capable of fixing ammonia (glutamic dehydrogenase, alanine dehydrogenase, L-amino acid oxidase, etc.). The fixation of ammonia in the glutamine synthetase system will be discussed in Chapter 17. The present section will deal with (a) enzymes which fix ammonia to form carbamyl phosphate and (b) enzymes which utilize carbamyl phosphate for the synthesis of arginine (and urea) and pyrimidines. 

Enzymes, measured in clinical laboratories, for which kits are available include y-glutamyl transferase (GGT), alanine transferase [9000-86-6] (ALT), aldolase, a-amylase [9000-90-2] aspartate aminotransferase [9000-97-9], creatine kinase and its isoenzymes, galactose-l-phosphate uridyl transferase, Hpase, malate dehydrogenase [9001 -64-3], 5 -nucleotidase, phosphohexose isomerase, and pymvate kinase [9001-59-6]. One example is the measurement of aspartate aminotransferase, where the reaction is followed by monitoring the loss of NADH ... 

Acylation reaction, 171 Alanine, structure of, 110 Alcohol dehydrogenase, 205 Amide hydrolysis, see also Serine proteases Trypsin... 

Many dehydrogenase enzymes catalyze oxidation/reduction reactions with the aid of nicotinamide cofactors. The electrochemical oxidation of nicotinamide adeniiw dinucleotide, NADH, has been studied in depthThe direct oxidation of NADH has been used to determine concentration of ethanol i s-isv, i62) lactate 157,160,162,163) pyTuvate 1 ), glucose-6-phosphate lactate dehydrogenase 159,161) alanine The direct oxidation often entails such complications as electrode surface pretreatment, interferences due to electrode operation at very positive potentials, and electrode fouling due to adsorption. Subsequent reaction of the NADH with peroxidase allows quantitation via the well established Clark electrode. 

ALT, alanine aminotransferase AST, aspartate aminotransferase GGT, gamma-glutamyl transferase INR, international normalized ratio LDH, lactate dehydrogenase PT, prothrombin time. 

Lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, total bilirubin, alkaline phosphatase. 

Laboratory evaluation frequently shows leukocytosis, increases in creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and myoglobinuria. 

Alkaline phosphatase 5 -Nudeotidase fGlutamyltransferase Aspartate aminotransferase Alanine aminotransferase Lactate dehydrogenase... 

Glutamate dehydrogenase D-amino acid oxidase Standard solution D-alanine... 

L-Amino acid oxidase has been used to measure L-phenylalanine and involves the addition of a sodium arsenate-borate buffer, which promotes the conversion of the oxidation product, phenylpyruvic acid, to its enol form, which then forms a borate complex having an absorption maximum at 308 nm. Tyrosine and tryptophan react similarly but their enol-borate complexes have different absorption maxima at 330 and 350 nm respectively. Thus by taking absorbance readings at these wavelengths the specificity of the assay is improved. The assay for L-alanine may also be made almost completely specific by converting the L-pyruvate formed in the oxidation reaction to L-lactate by the addition of lactate dehydrogenase (EC 1.1.1.27) and monitoring the oxidation of NADH at 340 nm. 

A biosensor was designed where a dehydrogenase and an enlarged coenzyme are confined behind an ultrafiltration membrane. The amino acid is determined indirectly, by measuring the fluorescence of the reduced coenzyme (kex 360 nm, kfl 460 nm) produced in reaction 22, with the aid of an optical fiber. The coenzyme is regenerated with pyruvate in a subsequent step, as shown in reaction 23. This biosensor was proposed for determination of L-alanine and L-phenylalanine for monitoring of various metabolic diseases and for dietary management363. 

ALT = alanine aminotransferase AST = aspartate aminotransferase Bd Wt = body weight Cardio = cardiovascular d = day(s) F = female GLDH = glutamate dehydrogenase Gn Pig = guinea pig Hemato = hematological hr = hour(s) LDH = lactate dehydrogenase LOAEL = lowest-observed-adverse-effect level M = male min = minute(s) ... 

Hepatic Effects. Enlarged liver and elevated serum levels of hepatic enzymes indicative of liver injury (lactate dehydrogenase, 2 times above normal aspartate aminotransferase, 21 times above normal alanine aminotransferase, 100 times above normal) were observed in an individual following chronic daily exposure to vapors and spills of phenol (Merliss 1972). The symptoms lessened when the... 

Elevated activities of liver enzymes (lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, glutamate dehydrogenase) were found in the serum of rats exposed continuously to 26 ppm phenol vapor for 15 days (Dalin and Kristoffersson 1974). Increased concentration of these enzymes in serum is often associated with liver injury but is not conclusive evidence for the type or severity of injury. Therefore, 26 ppm can be considered a less serious LOAEL in rats. Serum levels of... 

Hepatic Effects. Two days after a man was splashed with a phenol-water solution over his face, chest wall, hand, and both arms, serum bilirubin increased 2-fold (Horch et al. 1994). After 5 days, serum bilirubin returned to normal. An enlarged and tender liver and increased liver enzymes in the serum were reported in a case of chronic phenol poisoning (Merliss 1972). Lactate dehydrogenase was about 2-fold greater than normal, aspartate aminotransferase was about 21-fold greater than normal, and alanine aminotransferase was about 100-fold greater than normal. The man worked in a laboratory for 13.5 years where he distilled phenol several times a day. During the process, heavy odors were detectable, phenol was often spilled on his clothes, and he noted skin irritation. 

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