POLYOL DEHYDROGENASE: PURIFICATION. EVIDENCE FOR MULTIPLE FORMS AND SOME PROPERTIES OF THE DOMINANT VARIANT OF THE HORSE LIVER ENZYME |
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| Authors: | G F Porter E T McGuinness |
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| Institution: | 1. DEPARTMENT OF CHEMISTRY , SETON HALL UNIVERSITY , SOUTH ORANGE, NEW JERSEY, 07079;2. Department of Chemistry , Upsole College , East Orange, NJ, 07016 |
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| Abstract: | Purification of horse-liver polyoi dehydrogenase (PDH) on DE52 anion-exchange cellulose reveals the presence of three fractions with enzyme activity. These appear in the breakthrough volume (PDH-3) and the salt gradient (PDH-1, -2) respectively. The major band of activity (< 90%) is found in the PDH-2 fraction. A reexamination of sheep-liver polyol dehydrogenase also reveals the presence of three bands of activity, with the dominant fraction (PDH-3) corresponding to the preparation described by Smith (Biochem. J., 83, 135–144, (1962))3. The interaction between horse-liver (and sheep-liver) PDH and Blue Sepharose CL-6B is found to be endothermic. This property is utilized in the final purification step. Horse-liver PDH-2 has a molecular/subunit weight of 85, 000/28, 000, a Stokes' radius of 3.8 nm, and an isoelectric point of 7.4. |
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| Keywords: | diastereomers diastereoselectivity L-erythro-DOPS L-threo-3 4-dihydroxyphenylserine (L-threo-dops) L-threonine aldolase mutation optimization |
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