Horse liver primary structure

Ammer, D., Lerch, K. Primary structure of horse liver superoxide dismutase. In Chemical and Biochemical Aspects of Superoxide and Superoxide Dismutase (Bannister, J. V., Hill, H. A. O., eds.). New York-Amsterdam-Oxford, Elsevier/North-Holland, 1980, pp. 230-236 Jabusch, J. R. et al. Biochemistry i9, 2310 (1980)... 

It is also the case that enzymes showing sequence similarities do not necessarily catalyse the same reactions. Sheep liver sorbitol dehydrogenase (EC 1.1.1.14) does not utilize ethanol, though in primary structure it resembles both yeast and horse liver alcohol dehydrogenases [5,6]. 

The EE and SS isozymes of horse liver alcohol dehydrogenase have very similar primary structures [7,8]. Ethanol is a substrate for both, but both have a wide specificity, and ethanol is not the best substrate for either. The SS isozyme has 3/3-hydroxysteroid dehydrogenase activity [9,10], which the EE isozyme does not have, and which is thought to depend upon a single amino acid replacement [11], It remains to be established whether these different isozymes have different roles in vivo. 

Yeast and mammalian alcohol dehydrogenases differ in substrate specificity and catalytic activity. The yeast enzyme is more specific for acetaldehyde and ethanol, but mammalian enzymes have a broad substrate specificity, and even with primary alcohols maximum activity is not observed with ethanol. Because of the large amount of alcohol dehydrogenase present in human liver and its role in alcohol metabolism in man, human liver alcohol dehydrogenase is of particular interest. It was first purified by Wartburg et and crystallized by Mourad and Woronick. Human liver alcohol dehydrogenase is a dimer with subunit structures analogous to those of horse liver, and each subunit probably contains two zinc atoms. Several different types of human ADH have been isolated. with minor variations in amino acid... 

Horse liver ADH is a very universal enzyme with a broad substrate specificity and excellent stereoselectivity. Historically, it is the most widely used dehydrogenase in biotransformations [775, 776]. The three-dimensional structure has been elucidated by X-ray diffraction [778]. Although the primary sequence is quite different, the tertiary structure of HLADH is similar to that of YADH [779]. The most useful applications of HLADH are found in the reduction of medium-ring monocyclic ketones (four- to nine-membered ring systems) and bicyclic ketones [780-782]. Sterically demanding molecules which are larger than decalines are not readily accepted and acyclic ketones are usually reduced with modest enantioselec-tivities [783, 784]. 

Jomvall H, Harris JI (1970) Horse liver alcohol dehydrogenase. On the primary structure of the ethanol-active isoenzyme. Eur J Biochem 13(3) 565-576... 

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