ADH isozyme

All forms of human ADH are dimeric zinc-metalloenzymes comprised of subunits with molecular masses of approximately 40,000, and are located in the cytoplasm. The different ADH isozymes are grouped into five classes based on their... 

Retrieve complete CDS of human alcohol dehydrogenase (ADH) isozymes from UniGene and record the comparison with other organisms (UniGene listings). 

Fig. 36a-c. LDH- and ADH-isozyme patterns of trout liver, 150 (left) and 192 (right) days after fertilization a Salmo trutta b hybrid c S. irideus. (After Hit-zero th et al., 1968)... 

Horse liver alcohol dehydrogenase, HLADH, (also abbreviated as ADH or LADH) is the most extensively studied oxido-reductase. It plays a central role in ethanol metabolism and has been one of the main tools for understanding the mechanism of this process.15 it was crystaliized from horse liver in 1948 by Bonnichen and Wassen and is commercially available. Three isozymes EE, ES and SS are formed by dimeric combination of two different, E or S (E "ethanol-active" and S "steroid active"), protein chains. 16 The EE- isozyme of HLADH has been used in organic synthesis. 

PsADH2 is not expressed under aerobic or fermentative conditions unless PsADHl is disrupted. The inabiHty of the Psadh double disruptant to grow on ethanol under full aerobiosis suggests that no other Adh activities are present under these conditions, but the continued ethanol production under oxygen-Hmited conditions implies that other isozymes exist. Indeed, evidence of a third Adh can be seen in some Southern blots of P. stipitis DNA. The gene for a third isoenzyme may be present but not expressed on ethanol under aerobic conditions. 

In higher organisms, isozymes frequently have different organal distributions (62,66,471). In this respect, the retinal alcohol dehydrogenase was of special interest because of its possible role in conversion of retinene (1,473). The retinal enzyme, however, apparently lacks this capacity and is different from the liver enzyme (81,474). ADH also occurs in other organs outside the liver (62,66,476,476). Different intracellular distributions of isozymes (477) and an isozyme dependency on the culture medium (478) are also known for other species than the Saccharomyces (Section III,A). Completely (Section IV,C 479) or partially (480) ADH-deficient mutants are known in some species. 

Different species of higher plants contain ADH. The peanut enzyme has been purified and shown to be a zinc metalloenzyme (488). From tea seeds a mixture of two isozymes of molecular weight 150,000 have been purified and foimd to be unstable in the absence of thiols (439). Partially purified pea ADH is also unstable (490). Other species in which the enzyme is present, apart from those previously reviewed (1), include oats (491), barley (493), and wheat (493). The occurrence of isozymes has been noticed in wheat (494) ... 

ADH is active as a dimer, with an active site containing zinc present in each subunit. The human has at least seven genes that encode isozymes of ADH, each with a slightly different range of specificities for the alcohols it oxidizes. 

III ADH 5 X Ubiquitously expressed, but at higher levels In liver. The only Isozyme present In germinal cells. Relatively inactive toward ethanol. Active mainly toward long-chain alcohols, and lo-OH fatty acids. 

There is no gene which regulates the ADH gene. When considering the tissue specificity of enzyme distribution and the dynamics of changes in isozyme patterns, however, this conclusion seems doubtful. 

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