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The Intermediate in the Uridine Diphosphate Galactose P-Epimerase Reaction
| Content Provider | Semantic Scholar |
|---|---|
| Copyright Year | 2003 |
| Abstract | Incubation of UDP-galactose with substrate amounts of UDP-galactose 4-epimerase (EC 5.1.3.2) from Escherichia coli for different times between 2 and 120 min, followed by reduction with NaB3H4 invariably yields a mixture of labeled UDP-glucose and UDP-galactose. Chemical degradation of tritiated hexoses, isolated after NsB3H4 reduction of 2-min incubation mixtures, shows all of the tritium associated with carbon 4, in agreement with the results presented earlier using longer incubation times (MAITRA, U. S., AND ANKEL, H. (1972) hoc. Nat. Acad. Sci. U. S. A. 68, 2660). The total amount of label introduced after 2 min of incubation, when enzyme activity is practically unchanged, is considerably less than that after 120 min of incubation, when enzyme activity is reduced to about 50%. The excess of labeled UDPhexoses after 120 min of incubation can be quantitatively related to the amount of inactive enzyme formed, assuming that during inactivation additional UDP4-ketohexose is produced in amounts equivalent to the amounts of inactive enzyme. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.jbc.org/content/248/4/1477.full.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
