Question 1: If the pre-formed microtubules are resuspended, aliquoted and snap-frozen as directed, will they depolymerize and need to be re-polymerized or is the polymerized state maintained during one freeze and thaw cycle?
Answer 1: The pre-formed microtubules (Cat. # MT002) will not depolymerize upon one freeze thaw cycle. Thaw rapidly in a room temperature water bath and then keep at room temperature until ready to use. However, when aliquoting for snap-freezing, pipette smaller volumes (10-20 ul) since the concentration of the microtubules will be 1 mg/ml (based on datasheet instructions).
Question 2: What is the difference between the two different versions of pre-formed microtubules (Cat. # MT001 and MT002)?
Answer 2: The only difference between the MT001 pre-formed microtubules and the MT002 pre-formed microtubules is the source of the tubulin used to product the microtubules. MT001 uses bovine brain and MT002 uses porcine brain. In side-by-side comparisons (please see the MT002 datasheet), the microtubule-activated kinesn ATPase activity (Cat. # BK053) of MT001 (bovine) and MT002 (porcine) microtubules was compared. Both sources of microtubules produced the same results with this kinesin ATPase end-point assay (Cat. # BK053).
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