active site

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ac·tive site

that portion of an enzyme molecule at which the actual reaction proceeds; considered to consist of one or more residues or atoms in a spatial arrangement that permits interaction with the substrate to effect its reaction.

active site

The part of an enzyme at which catalysis of the substrate occurs.

active site

the place on the surface of an enzyme where its catalytic action occurs.

Active Site

The site in an enzyme where a substrate binds and an enzymatic reaction—e.g., ligation, oxidoreduction, etc.—occurs. The structure of the amino acid residues within the active site enhances substrate binding, substrate activation, and formation of a transition state.

ac·tive site

(ak'tiv sīt)
That portion of an enzyme molecule at which the actual reaction proceeds; one or more residues or atoms in a spatial arrangement that permits interaction with the substrate.

active site

1. The region of an ENZYME to which the substance being affected binds so as to undergo a catalyzed reaction.
2. The localized part of a protein to which a substrate binds.
Active siteclick for a larger image
Fig. 11 Active site . Lock-and-key mechanism of enzyme activity.

active site

an area of ENZYME surface which has a shape complementary to a particular SUBSTRATE, enabling the enzyme and substrate to become temporarily bonded to form an enzyme-substrate complex. Such a lock-and-key mechanism explains the great specificity of enzymes for substrates and also why changes in enzyme three-dimensional shape (by pH, temperature) cause alterations to enzyme activity.


not passive.

active principle
the drugs or chemicals in a pharmaceutical preparation that exert an effect pharmacologically; as distinct from the inert fillers, wetting agents and other excipients also often included.
active site
that region of a protein, usually an enzyme, that binds to another molecule such as the substrate of the enzyme.
active transport
the movement of ions or molecules assisted by a carrier protein across the cell membranes and epithelial layers, usually against a concentration gradient, resulting directly from the expenditure of metabolic energy. For example, under normal circumstances more potassium ions are present within the cell and more sodium ions extracellularly. The process of maintaining these normal differences in electrolytic composition between the intracellular fluids is active transport. The process differs from simple diffusion or osmosis in that it requires the expenditure of metabolic energy.

Patient discussion about active site

Q. Are there any nice activities for adults with autism? I've been helping a very nice man of 45 of years old and I'm looking for some new things I can do with him in our time together. any ideas?

A. Autistic people react wonderfully with animals. for instance- i saw a group of severe Autistic teenagers going to swim with dolphins. the effect was amazing! taking him to the zoo, or even to the park to feed ducks, pet dogs, whatever.. could have a great effect on him.
hope i helped!
tell me how it went.

Q. what is a passive smoking? and is it dangerous as an active?

A. Passive smoking is the exposure to cigarettes smoke emitted from cigarettes smoke by other person. It's dangerous and may increase the risk to several diseases similar to active smoking (one's exposure to smoke emitted from the cigarettes he or she is smoking) although the risk is of lower magnitude. Example for passive smoking is children of smokers etc.

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Q. i swim a lot ! what are the advantages of swimming over other sport activities? on what part of the body does it work the most ?

A. its a good workout but your not really going to burn as much calories as a regular work out.

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References in periodicals archive ?
The command line will be used to adjust the image to our desired region of study, which is the active site.
Flap/lid protecting active siteIn the case of lipase TcL, the amino acid residues from Leu226 to Ile257 make a protective loop over the surface of the lipase which protects the active site and makes it inaccessible to solvent and renders the core of the enzyme hydrophobic.
Much attention has been dedicated to polydispersities because of the likely existence of multiple active sites and of the difficulty to reproduce the catalyst synthesis.
His work has contributed meaningfully to the better understanding of the nature of the active sites and the reaction mechanism in these systems, which is valuable information for designing better catalysts and processes.
In the period of the trading update, Barratt said it operated from an average of 349 active sites.
Because C289 is located at the entrance to the active site of AChE, it potentially could react with chemical pesticides designed to target that enzyme.
5 A resolution was confirmed, whereas the two active site histidines had to be rotated around CBCG bonds in order to agree with the difference maps.
PME-1 is highly conserved from yeast to human and contains a motif found in lipases, which motif has a catalytic triad-activated serine as the active site nucleophile.
An inhibitor of HIV protease, Kaletra binds to the enzyme's active site, disrupting its normal function.
A visitor, escorted up a four-mile dirt road by Leonard and another guard armed with guns and a crackly walkie-talkie, found McLaren inside the old firehouse, surrounded by mounds of legal documents, computers (the group has a highly active site on the World Wide Web), fax machines and a television with an impressive collection of video movies, including ``Hard to Kill'' and ``Thelma and Louise.
b) particle growth achieved via the integration of polymer growth at each active site within the particle.

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