PROTEIN-PHOSPHORYLATION IN HUMAN PERIPHERAL-NERVE - ALTERED PHOSPHORYLATION OF A 25-KDA GLYCOPROTEIN IN LEPROSY

Protein phosphorylation in a low speed supernatant of human peripheral nerve (tibial and sural) homogenate was investigated. The major phosp horylated proteins had molecular mass in the range of 70, 55, 45, and 25 kDa. Mg2+ or Mn2+ was essential for maximum phosphorylation althoug h Zn2+, Co2+, and Ca2+ could partially support phosphorylation. Extern al protein substrates casein and histone were also phosphorylated. The protein phosphatase inhibitor orthovanadate enhanced the phosphorylat ion of the 45 and 25 kDa proteins significantly. Concanavalin A-Sephar ose chromatography of the phosphorylated peripheral nerve proteins sho wed that the 25 kDa protein was a glycoprotein. Protein phosphorylatio n of peripheral nerves from leprosy affected individuals was compared with normals. The phosphorylation of 25 kDa protein was decreased in m ost of the patients with leprosy.