Identification of Nsp100 as elongation factor 2 (EF‐2)

Abstract
The nerve growth factor‐sensitive phosphoprotein from PC12 cells, previously designated Nsp100, has been shown to be elongation factor 2 (EF‐2). The criteria used for this identification include: (i) similarity of N‐terminal sequence; (ii) phosphorylation by the same kinase; (iii) ADP‐ribosylation mediated by diphtheria toxin; (iv) comparable function in cell‐free protein synthesis. According to these criteria, Nsp 100 and EF‐2 are identical and the kinase that phosphorylates Nsp100 in PC12 cells is calcium/calmodulin kinase III.