| First Author | Novikov AM | Year | 1991 |
| Journal | Biochem Genet | Volume | 29 |
| Issue | 11-12 | Pages | 627-38 |
| PubMed ID | 1820026 | Mgi Jnum | J:1974 |
| Mgi Id | MGI:50498 | Doi | 10.1007/bf02426876 |
| Citation | Novikov AM, et al. (1991) Ganglioside GD3 biosynthesis in normal and mutant mouse embryos. Biochem Genet 29(11-12):627-38 |
| abstractText | CMP-sialic acid:GM3 sialyltransferase (GD3 synthase; EC 2.4.99.8) was characterized in a membrane-enriched preparation (P2 pellet) from mouse embryos at embryonic day 12 (E-12). Gangliosides GD3 and GM3 were the major radiolabeled products of the reaction. Optimum GD3 synthase activity was obtained at pH 6.0 using 0.1% detergent Triton CF-54. The Km values for GM3 and CMP-sialic acid were 55 and 80 microM, respectively. The Vmax value was calculated as 622 pmol/mg protein/hr. Ganglioside GD3, as end product, induced a two-step reduction of enzyme activity in the range of concentrations from 0 to 34 microM (40%) and from 150 to 300 microM (65%). The rate of GD3 formation was similar in whole embryos and in embryo head and body regions. GD3 synthase activity in tw1/tw1 mutant mouse embryos, which express defects in neuronal differentiation, was only 40% of that in normal wild-type (+/+) embryos. Enzyme activity in heterozygous (+/twl) embryos was similar to that in +/+ embryos. These findings suggest that the reduced GD3 synthase activity in the mutants might arise as a consequence of failed nervous system development and might reflect a secondary rather than a primary effect of the mutation. |
