תפריט נגישות
ניגודיות עדינהניגודיות גבוהה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם תפריט נגישותניגודיות עדינהניגודיות גבוההמונוכרוםהדגשת קישוריםחסימת אנימציהפונט קריאסגוראיפוס הגדרות נגישותלהורדת מודול נגישות חינםFrances M. DuPont - USDA-ARS-WRRC, 800 Bachanan St., Albany CA 94710, USA
Microsomal membranes isolated from barley roots (Hordeum vulgare L. cv. CM72) contained endogenous protein phosphorylation activities that were greatly enhanced by Mn2+. Mg2+ions also stimulated protein phosphorylation, but to a lesser extent than Mn2+. Ca2+ enhanced Mg2+, but not Mn2+-dependent phosphorylation. It is proposed that this strong enhancement by Mn2+ may be due to a greater affinity of Mn2+ than either Ca2+ or Mg2+ for both the Ca2+ and Mg2+ binding sites of certain kinases. Some Mn2+ stimulated kinase activity was eliminated from the membrane by washing with 0.2 mol/L KCl. The KCl extract contained histone and casein kinase activities, and 4 major phosphoproteins that were phosphorylated on serine and threonine residues. Phosphorylation of a 52 kDa polypeptide corresponded with the characteristics of the histone kinase activity and may represent the autophosphorylation of a CDPK-type kinase. Phosphorylation of a 36 kDa polypeptide was Ca2+ stimulated and may represent the autophosphorylation of a different type of unknown kinase. Polypeptides of 18 and 15 kDa had characteristics that suggest they were autophosphorylating subunits of a membrane bound nucleotide di-phosphokinase.
Frances M. DuPont - USDA-ARS-WRRC, 800 Bachanan St., Albany CA 94710, USA
Microsomal membranes isolated from barley roots (Hordeum vulgare L. cv. CM72) contained endogenous protein phosphorylation activities that were greatly enhanced by Mn2+. Mg2+ions also stimulated protein phosphorylation, but to a lesser extent than Mn2+. Ca2+ enhanced Mg2+, but not Mn2+-dependent phosphorylation. It is proposed that this strong enhancement by Mn2+ may be due to a greater affinity of Mn2+ than either Ca2+ or Mg2+ for both the Ca2+ and Mg2+ binding sites of certain kinases. Some Mn2+ stimulated kinase activity was eliminated from the membrane by washing with 0.2 mol/L KCl. The KCl extract contained histone and casein kinase activities, and 4 major phosphoproteins that were phosphorylated on serine and threonine residues. Phosphorylation of a 52 kDa polypeptide corresponded with the characteristics of the histone kinase activity and may represent the autophosphorylation of a CDPK-type kinase. Phosphorylation of a 36 kDa polypeptide was Ca2+ stimulated and may represent the autophosphorylation of a different type of unknown kinase. Polypeptides of 18 and 15 kDa had characteristics that suggest they were autophosphorylating subunits of a membrane bound nucleotide di-phosphokinase.
