Folic acid effects on glycoprotein-galactosyltransferase: A re-assessment
| Autor: | Lois M. Geren, K.E. Ebner |
|---|---|
| Rok vydání: | 1974 |
| Předmět: |
Fetal Proteins
Ovalbumin Phosphatase Biophysics Kidney Biochemistry Pyrophosphate chemistry.chemical_compound Folic Acid Mammary Glands Animal Pregnancy Alpha-Globulins Glycosyltransferase Animals Lactation Nucleotide Carbon Radioisotopes Molecular Biology Glycoproteins chemistry.chemical_classification Galactosyltransferase Glucosamine biology Galactose Lysophosphatidylcholines Cell Biology Uridine Diphosphate Sugars Fetuin Adenosine Monophosphate Rats Kinetics Milk Hexosyltransferases chemistry Chromatography Gel biology.protein Cattle Female Glycoprotein |
| Zdroj: | Biochemical and Biophysical Research Communications. 59:14-21 |
| ISSN: | 0006-291X |
| DOI: | 10.1016/s0006-291x(74)80167-1 |
| Popis: | Summary Previous studies (1) have reported that folic acid increases the activity of several glycosyltransferases, including a galactosyltransferase of rat liver and kidney suggesting that folic acid may be involved in the control of glycoprotein biosynthesis. The present study provides an explanation for the previous results using a galactosyltransferase which transfers galactose to both a fetuin acceptor and N-acetylglucosamine. If the UDP-galactose is 1.5 μM in the assay there is stimulation by 1.4 mM folic acid or 5 mM 5′-AMP but there is not stimulation when the UDP-galactose is 0.6 mM. Crude homogenates contain a nucleotide pyrophosphate and phosphatase which liberate galactose from UDP-galactose. Both folic acid and 5′-AMP inhibit the nucleotide pyrophosphatase which protects the substrate and this becomes significant when the UDP-galactose concentration is low. Purified galactosyltransferase is inhibited by both folic acid and 5′-AMP. The observed stimulation of galactosyltransferase in crude systems by folic acid or AMP is due to substrate protection and it is therefore unlikely that folic acid is involved in the control of glycoprotein synthesis. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|