Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.6.4.1 (
myosin ATPase
)
1,140
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Mercury reduces twitch and tetanic force development in isolated rat papillary muscles, and a putative toxic effect on the contractile machinery has been suggested. Based on that, the actions of
HgCl2
on the
myosin ATPase
activity of the left ventricular myocardium were investigated. Samples for assay of
myosin ATPase
activity were obtained from rats' left ventricles. Increasing concentrations of
HgCl2
reduced dose-dependently the activity of the
myosin ATPase
. This reduction was observed even at very small concentrations, 50 nM
HgCl2
. This effect was dependent on the presence of SH groups in the myosin molecule since DTT and glutathione protected the
myosin ATPase
against toxic effects of mercury; full activity being restored by using 500 nM DTT or 500 nM glutathione. Results also suggested that the metal acts as an uncompetitive inhibitor with a Ki of 200 nM
HgCl2
. Our results suggest that mercury reduces the activity of the
myosin ATPase
by an uncompetitive mechanism at a very low dose that does not depress force. DTT and glutathione are effective for protection against the actions of mercury suggesting that SH groups might be the sites of action of the metal on the myosin molecule.
...
PMID:Effects of mercury on myosin ATPase in the ventricular myocardium of the rat. 1292 1
We explored the potential of contractile proteins, actin and myosin, as biosensors of solutions containing mercuric ions. We demonstrate that the reaction of
HgCl2
with myosin rapidly inhibits actin-activated
myosin ATPase
activity. Mercuric ions inhibit the in vitro analog of contraction, namely the ATP-initiated superprecipitation of the reconstituted actomyosin complex. Hg reduces both the rate and extent of this reaction. Direct observation of the propulsive movement of actin filaments (10 nm in diameter and 1 microm long) in a motility assay driven by a proteolytic fragment of myosin (heavy meromyosin or HMM) is also inhibited by mercuric ions. Thus, we have demonstrated the biochemical, biophysical and nanotechnological basis of what may prove to be a useful nano-device.
...
PMID:A novel biosensor for mercuric ions based on motor proteins. 1559 Feb 99
