Question 1: How does general tubulin buffer differ from G-PEM buffer?
Answer 1: Basically, these buffers are the same except that G-PEM contains 1mM GTP to support tubulin polymerization. General tubulin buffer ((Cat. #BST01) and PEM buffer typically contain 80 mM PIPES, 2 mM MgCl2, 0.5 mM EGTA pH 7.0. Both buffers should be supplemented with 1 mM GTP (hence, the &ldquo, G&rdquo, in G-PEM buffer).
Question 2: Is glycerol necessary for the maintenance of biologically-active tubulin?
Answer 2: Glycerol is often added to a final concentration of 5 - 10% to enhance polymerization, however, glycerol is not necessary for the maintenance of biologically active tubulin.