PMID- 7225365
OWN - NLM
STAT- MEDLINE
DCOM- 19810723
LR  - 20190613
IS  - 0006-2960 (Print)
IS  - 0006-2960 (Linking)
VI  - 20
IP  - 7
DP  - 1981 Mar 31
TI  - Kinetic analysis of guanosine 5'-triphosphate hydrolysis associated with tubulin 
      polymerization.
PG  - 1918-24
AB  - The correlation between the time courses of pure tubulin assembly and 
      accompanying guanosine 5'-triphosphate (GTP) hydrolysis has been studied at 
      different tubulin concentrations in the range where the rate of assembly varies 
      with a strong cooperativity. One GTP molecule was found hydrolyzed per molecule 
      of tubulin dimer incorporated in the microtubule. This hydrolysis was not 
      strictly coupled to polymerization and occurred in a subsequent step. 
      Consequently, in the first stages of assembly, tubulin-GtP complex is the 
      transient major constituent of microtubules. Kinetic data of GTP hydrolysis have 
      been treated within a model of two consecutive first-order reactions: 
      [tubulin-GTP]free k1 leads to [tubulin-GTP]MT k2 leads to [tubulin-GDP]MT + [Pi] 
      GTP hydrolysis proceeded at an intrinsic rate k2 = 0.25 min-1 independent of 
      tubulin concentration. Simultaneous measurements of polymerization, GTPase 
      activity, and incorporation of [3H]GTP followed by unlabeled GTP chase indicated 
      that before its hydrolysis GTP bound to microtubules was exchangeable while after 
      hydrolysis GDP remained locked in the E site. The possibility is discussed that 
      after assembly tubulin undergoes a conformation change which could trigger GTP 
      hydrolysis and sequestration of GDP.
FAU - Carlier, M F
AU  - Carlier MF
FAU - Pantaloni, D
AU  - Pantaloni D
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Biochemistry
JT  - Biochemistry
JID - 0370623
RN  - 0 (Macromolecular Substances)
RN  - 0 (Phosphorus Radioisotopes)
RN  - 0 (Tubulin)
RN  - 10028-17-8 (Tritium)
RN  - 86-01-1 (Guanosine Triphosphate)
SB  - IM
MH  - Animals
MH  - Brain/*metabolism
MH  - Guanosine Triphosphate/*metabolism
MH  - Hydrolysis
MH  - Kinetics
MH  - Macromolecular Substances
MH  - Microtubules/ultrastructure
MH  - Phosphorus Radioisotopes
MH  - Swine
MH  - Tritium
MH  - Tubulin/*metabolism
EDAT- 1981/03/31 00:00
MHDA- 1981/03/31 00:01
CRDT- 1981/03/31 00:00
PHST- 1981/03/31 00:00 [pubmed]
PHST- 1981/03/31 00:01 [medline]
PHST- 1981/03/31 00:00 [entrez]
AID - 10.1021/bi00510a030 [doi]
PST - ppublish
SO  - Biochemistry. 1981 Mar 31;20(7):1918-24. doi: 10.1021/bi00510a030.