Alanine dehydrogenase EC

An enzyme from Bacillus sphaericus [100] catalyses this reaction. Like the well-known glutamate dehydrogenases it has a hexameric subunit arrangement, and is specific 

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In some microorganisms, ammonia assimilation may also occur by alanine synthesis, catalysed by alanine dehydrogenase (EC 1.4.1.1). 

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. 

EC 1.4.1.1 Alanine dehydrogenase pyruvate+nadred+ammonia=alanine+nadox+h2o... 

Although it is not recommended by the EC, it is a common and convenient practice to use capital letter abbre viations for the names of certain enzymes, such as ALT (formerly GPT) for alanine aminotransferase (EC 2.6.1.2). Other examples are AST for aspartate aminotransferase, LD for lactate dehydrogenase, and CK for creatine kinase (see Table 8-1). 

Pyruvate may also be converted into alanine by transamination and is reduced by L-lactate dehydrogenase (EC 1.1.1.27) (Holbrook etaL, 1975), the latter reaction providing the basis for the lactic acidosis and lactic aciduria that are observed in primary inherited disorders of pyruvate metabolism and as secondary phenomena in several other metabolic diseases. These latter include... 

This enzyme [EC 1.5.1.17] catalyzes the reversible reaction of 2,2 -iminodipropanoate with water and NAD+ to produce alanine, pyruvate and NADH. In the reverse reaction, alanine can be replaced as a substrate by cysteine, serine, or threonine. Glycine acts very slowly as a substrate (that is, the reaction catalyzed by strombine dehydrogenase). 

There are five enzymes that are commonly used in diagnosis of liver disease Aspartate aminotransferase (AST EC 2.6.1.1), alanine aminotransferase (ALT EC 2.6.1.2), alkaline phosphatase (ALP 3.1.3.1), and y-glutamyl transferase (GGT EC 2.3.2.2), are commonly used to detect liver injury, and lactate dehydrogenase (LD EC 1.1.1.27) is occasionaEy used. ALT and GGT are present in several tissues, but plasma activities primarily reflect liver injury. AST is found in liver, muscle (cardiac and skeletal), and to a liipited extent iti fed cells. LD has wide tissue distribution, and is thus relatively nonspecific. ALP is found in a number of tissues, but in normal individuals primarEy reflects bone and liver sources. Thus based on tissue distribution, ALT and GGT would seem to be the most specific markers for liver injury. 

Lactate is usually determined by photometric detection of NADH formed in the reaction catalyzed by lactate dehydrogenase (LDH, EC 1.1.1.27). The pH optimum for the forward reaction of LDH (MW 135 000) is about 9, the Km for lactate 6.7 mmolA. Since the equilibrium lies far to the left (K = 2.76-10-5 mol/1 at pH 7.0), hydrazine, pyruvate oxidase, or alanine aminotransferase have to be added to trap the pyruvate formed. 

ADP AFP ab as ALAT AP ASAT ATP BQ BSA CEH CK CME COD con A CV d D E E EC ECME EDTA EIA /e FAD FET FIA G GOD G6P-DH HBg HCG adenosine diphosphate a-fetoprotein antibody antigen alanine aminotranferase alkaline phosphatase aspartate aminotransferase adenosine triphosphate benzoquinone bovine serum albumin cholesterol ester hydrolase creatine kinase chemically modified electrode cholesterol oxidase concanavalin A coefficient of variation (relative standard deviation) layer thickness diffusion coefficient enzyme potential Enzyme Classification enzyme-chemically modified electrode ethylene diamine tetraacetic acid enzyme immunoassay enzyme loading factor flavin adenine dinucleotide field effect transistor flow injection analysis amplification factor glucose oxidase glucose-6-phosphate dehydrogenase hepatitis B surface antigen human chorionic gonadotropin... 

Though various methods for the determination of enzyme activity are used routinely in clinical laboratories, many of them are covered by patents, and the components of their test kits are not commercially available. In clinical chemistry, reference methods and certified enzyme reference materials (enzyme calibrators) for determination of activities of enzymes in human blood serum are recommended by international commissions (ISOTC/212, International Federation of Clinical Chemistry IFCC, Institute for Reference Materials and Measurements EU, etc.) at present for improved accuracy and establishment of traceability chains of the enzyme measurement system. By using these reference materials, the inaccuracy (imprecision between laboratories) has been minimized to within several per cent in several enzymes, such as lactate dehydrogenase (LDH) (EC 1.1.1.27), y-glutamyltrans-peptidase (y-GT) (EC 2.3.2.2), alanine aminotransferase (ALT) (EC 2.6.1.2), creatine kinase (CK) (EC 2.7.3.2), alkaline phosphatase (ALP) (EC 3.1.3.1), acid phosphatase (EC 3.1.3.2), and a-amylase (AMY)... 

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