Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.4.4 (kinesin)
 5,033 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Kinesin is a microtubule-activated, mechanochemical ATPase capable of moving particles along microtubules and making microtubules glide along a solid substrate. In this study we used limited proteolysis to study the structure of bovine brain kinesin, a heterotetramer composed of two heavy (120-kDa) and two light (62-kDa) chains. alpha-chymotrypsin, trypsin, and subtilisin all produced a protease-resistant 45-kDa fragment from the kinesin heavy chain. As isolated by gel-filtration chromatography, this fragment contains both the microtubule-binding site and the ATP catalytic site of the molecule. Proteolytic cleavage stimulated microtubule-dependent Mg2+-ATPase activity 4- to 5-fold up to 75-120 mumol ATP/min/mg. Cleavage also increased the affinity of the fragment for microtubules at least 10-fold. Since the purified fragment does not support the gliding of flagellar axonemes, we propose that cleavage of the heavy chain uncouples ATPase activity from its translocator activity, which may require other parts of the molecule.
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PMID:Isolation of a 45-kDa fragment from the kinesin heavy chain with enhanced ATPase and microtubule-binding activities. 252 Dec 21

Kinesin is a mechano-chemical ATPase capable to move particles along microtubules and microtubules along the solid substrate. Molecule of bovine brain kinesin is a heterotetrameric unit consisting of two heavy (120 kDa) and two light (62 kDa) chains. We used limited proteolysis to study the location of the functional sites on the kinesin molecule. Chymotrypsin cleavage produced a stable 45 kDa fragment of the heavy chain which was purified from the digest using FPLC chromatography on a Superose 12 column. 45 kDa fragment contained both a microtubule-binding site and a ATPase site of the kinesin molecule. Cleavage of the 45 kDa fragment from the rest of the heavy chain significantly activated its ATPase activity. However, this activity remained fully dependent on microtubules. We suggest that the chymotrypsin cleavage uncouple ATPase activity of kinesin (found in the 45 kDa fragment) from its translocator activity (which, probably, required the presence of other parts of the molecule).
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PMID:[45 kDa fragment of the kinesin molecule possesses high ATPase activity and binds to microtubules]. 252 60