PMID- 3753008
OWN - NLM
STAT- MEDLINE
DCOM- 19861008
LR  - 20190629
IS  - 0003-9861 (Print)
IS  - 0003-9861 (Linking)
VI  - 249
IP  - 2
DP  - 1986 Sep
TI  - The effects of elevated pH and high salt concentrations on tubulin.
PG  - 397-406
AB  - The effects of incubating phosphocellulose-purified bovine tubulin at 4 degrees C 
      in nucleotide-free buffers at alkaline pH or at high concentrations of NaCl, KCl, 
      (NH4)2SO4, or NH4Cl have been studied. At pH greater than or equal to 7.5 or at 
      NaCl concentrations greater than or equal to 0.7 M, tubulin releases bound 
      nucleotides irreversibly and loses, with apparent first-order kinetics, the 
      ability to assemble into microtubules. In 0.1 M 1,4-piperazinediethanesulfonic 
      acid buffer, pH 6.9, in the presence of 1.3 M NH4Cl, tubulin undergoes more rapid 
      loss of capacity to assemble than it does in NaCl and KCl, but 1.3 M (NH4)2SO4 
      causes no detectable change in tubulin after 1-h incubation. Incubation at high 
      pH or at high neutral salt concentrations also causes an apparently irreversible 
      change in the ultraviolet difference spectrum and in the sedimentation velocity 
      profile of tubulin. At elevated salt concentrations a decrease of approximately 
      10% in the molar ellipticity within the wavelength range 220-260 nm is observed. 
      The changes that occur during 1-h exposure to pH 8.0 can be completely prevented 
      by including 1 mM guanosine 5'-triphosphate (GTP) or 4 M glycerol in the buffer, 
      but those which occur at pH 9.0 cannot be prevented by these additions. In 1 M 
      NaCl when the ratio of bound guanine nucleotide to tubulin reaches approximately 
      1.0, tubulin loses the abilities to assemble into microtubules and to bind 
      colchicine. The rate of loss of nucleotide in 2 M NaCl is decreased in the 
      presence of 1 mM GTP, and tubulin is protected almost completely from 1 M 
      NaCl-induced loss of GTP (and retains the ability to exchange [3H]GTP as well) in 
      the presence of bound colchicine. Investigators who anticipate exposing tubulin 
      to buffers of elevated pH or high concentrations of chaotropic salts should be 
      extremely cautious in interpreting the resulting data unless they can demonstrate 
      that irreversible alteration of the protein has not occurred.
FAU - Croom, H B
AU  - Croom HB
FAU - Correia, J J
AU  - Correia JJ
FAU - Williams, R C Jr
AU  - Williams RC Jr
LA  - eng
GR  - GM25638/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Arch Biochem Biophys
JT  - Archives of biochemistry and biophysics
JID - 0372430
RN  - 0 (Guanine Nucleotides)
RN  - 0 (Tubulin)
RN  - SML2Y3J35T (Colchicine)
SB  - IM
MH  - Colchicine/metabolism
MH  - Guanine Nucleotides/*metabolism
MH  - Hydrogen-Ion Concentration
MH  - Osmolar Concentration
MH  - Protein Binding/drug effects
MH  - Spectrophotometry, Ultraviolet
MH  - Tubulin/*metabolism
EDAT- 1986/09/01 00:00
MHDA- 2001/03/28 10:01
CRDT- 1986/09/01 00:00
PHST- 1986/09/01 00:00 [pubmed]
PHST- 2001/03/28 10:01 [medline]
PHST- 1986/09/01 00:00 [entrez]
AID - 0003-9861(86)90016-0 [pii]
AID - 10.1016/0003-9861(86)90016-0 [doi]
PST - ppublish
SO  - Arch Biochem Biophys. 1986 Sep;249(2):397-406. doi: 10.1016/0003-9861(86)90016-0.