Rôle d'un intermédiaire lipidique dans le transfert du mannose à des accepteurs glycoprotéiques endogènes chez Aspergillus niger

AbstractPrevious studies from this laboratory have shown that a particulate preparation from Aspergillus niger catalyses the incorporation of mannose, from GDP-mannose, into a lipid fraction which has been identified as polyprenyl phosphate mannose (PPM). The results of kinetic studies presented in this communication suggest that PPM serves as an intermediate in the ensymatic transfer of mannosyl unit from GDP-mannose to endogenous glycoproteins. β-elimination or Pronase treatment and subsequent dialysis result respectively in 70% or 90% release of radioactivity. The absence of passive penetration of GDP-mannose across microsome membranes and the inhibitory effect of palmityl-CoA on mannose transfer are in good agreement with the involvement of PPM in the transport of mannose across membranes