Retinyl phosphate, synthesis

In the synthesis of most glycoproteins containing mannose, the intermediate carrier of the mannosyl moiety is the polyene dolichol phosphate. However, in some systems, retinyl phosphate can act as the intermediate carrier between UDP-mannose and the acceptor glycoprotein. Retinyl phosphate maimose seems to be involved especially in the synthesis of hydrophobic regions of glycoproteins (DeLuca, 1977 Frot-Coutaz et al., 1985). 

Martin and Thorne (1974) showed that microsomes from rat liver could synthesise both retinyl mannosyl phosphate and dolichyl mannosyl phosphate in vitro and with comparable efficiency, and Rosso et al (1975) found that retinol phosphate would stimulate retinyl mannosyl phosphate synthesis from GDP [ Man in a similar system, if ATP,Mn and lipid extract were added. 

Frot-Coutaz, Silverman-Jones and De Luca (1976) confirmed that retinol could be converted into retinyl phosphate by intact cells. Hamster intestinal epithelium was used and the product was characterised by a variety of partition and ion-exchange chromatographic procedures and by chemical comparison with an authentic (synthetic) sample of retinyl phosphate. Hence all the steps necessary for the synthesis of retinyl mannosyl phosphate from retinol could be demonstrated in the whole cell. 

Rosso, G., DeLuca, L., Warren, C.D. Wolf, G. (1975) Enzymatic Synthesis of Mannosyl Retinyl Phosphate from Retinyl Phosphate and Guanosine Diphosphate Mannose , Journal of Lipid Research, 16, 235-43... 

Rosso, G.C., Masushige, S., Warren, C.D., Kiorpes, T. Wolf, G. (1976) The Anomeric Configuration of the D-Mannosyl Retinyl Phosphate Formed in Rat Liver Microsomes , Journal of Biological Chemistry, 251, 6465-7 Rubery, P.H. Northcote, D.H. (1970) The Effect of Auxin (2,4-dichloro-phenoxyacetic Acid) on the Synthesis of Cell Wall Polysaccharides in Cultured Sycamore Cells , Biochimica et Biophysica Acta, 222, 95-108... 

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