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Next: 9. Immunochemistry Up: 8. Enzymes and Other Proteins Previous: Chymotrypsin

Alcohol dehydrogenase

These are zinc metalloenzymes that oxidize alcohols to aldehydes or ketones. Zinc is bound to the sulphur atoms of Cys-46 and Cys-174 and a nitrogen atom of His-67. An ionizable water molecule occupies the fourth position on the zinc. This water is hydrogen-bonded to the hydroxyl of Ser-48. The oxygen atom of substrate is believed to bind directly to the zinc ion. The nicotinamide ring of NAD+ is bound close to the zinc. In the oxidation of alcohol two hydrogen atoms are removed - one to the 4-position of NAD+ and the other as a proton. The transfer to NAD+ is generally throught to be hydride transfer.

References

Eklund, H., Nordstrom, B., Zeppezauer, E., Soderlund, G., Ohlsson, G., Bowie, T. and Branden, C. -I., FEBS Letters 44 (1974) 200: Eklund, H., Nordstrom, B., Zeppezauer, E., Soderlund, G., Ohlsson, I., Bowie, T., Soderberg, B.-O., Tapia, O., Branden, C.-I. and Akeson, A., J. Mol. Biol . 102 (1976) 27.



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