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The role of nucleoside diphosphatase in a uridine nucleotide cycle associated with lactose synthesis in rat mammary-gland Golgi apparatus.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Kuhn, Nicholas J. White, Abraham |
| Copyright Year | 1977 |
| Abstract | 1. UDP-galactose utilization by isolated Golgi vesicles or rat mammary gland synthesizing lactose causes accumulation of UMP but not UDP, although UDP is the immediate product of lactose synthase (EC 2.4.1.22). 2. This can be ascribed to a nucleoside diphosphatase (EC 3.6.1.6), specific for UDP, GDP and IDP, activated by bivalent metal ions and apparently located on the luminal face of the Golgi membrane. 3. The uridine diphosphatase activity exceeds the total galactosyltransferase activity 5-fold, and is estimated to maintain UDP at about 14 micrometer within the Golgi lumen. 4. Evidence is given that UMP, but not UDP, penetrates the membrane and that UMP is rephosphorylated to UDP by a UMP kinase located in the cytosol. 5. Golgi-cytosol relationships with respect to lactose synthesis are formulated in terms of a uridine nucleotide cycle which throws new light on the energy cost and possible regulation of lactose synthesis. |
| Starting Page | 95 |
| Ending Page | 95 |
| Page Count | 1 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://www.biochemj.org/content/ppbiochemj/168/3/423.full.pdf |
| PubMed reference number | 204286v1 |
| Volume Number | 168 |
| Issue Number | 3 |
| Journal | The Biochemical journal |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Cytoplasmic matrix Galactose Galactosyltransferases Guanosine Diphosphate Inosine Diphosphate Ions Lactose Synthase Lactose Synthesis Pathway Mammary gland Nucleosides Nucleotides Tissue membrane Uridine Diphosphate Uridine Monophosphate Vesicle (morphologic abnormality) galactosyltransferase activity negative regulation of pyrimidine nucleotide biosynthetic process positive regulation of ER to Golgi vesicle-mediated transport |
| Content Type | Text |
| Resource Type | Article |
