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

n.
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.

active

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.

You may read more here:http://www.nlm.nih.gov/medlineplus/secondhandsmoke.html

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 ?
This is confirmed by kinetic and spectral studies that showed that Roundup inhibits the enzyme at the active site level in a competitive manner.
Because the model identifies the active sites according to the fragmentation step when they were first exposed to monomer, the Table includes a column for each of the active site groups, The active [TABULAR DATA FOR TABLE 2 OMITTED] sites selected at the exterior region of the particle correspond to the largest concentration gradient across the polymer layer (polymer accumulation is higher for them when compared with those at any other radial position).
Active sites of proteins in the same family are often very alike and "confuse" drugs.
These X rays showed clearly that methyltransferase had, like an old-fashioned jukebox plucking a selected record out of a large stack and positioning it under a needle for playing, gracefully flipped a cytosine out of the stacked base pairs of the DNA and guided it into the enzyme's active site.
On binding to the enzyme, cyclinA swings the T loop out more than 2 nanometers, rotates another piece of CDK2 called the PSTAIRE helix through 90o, and moves the amino acids in the active site into the right conformation to bind proteins--dramatic changes, according to Pavletich.
This fascinating structure," says Lippard, "reveals the intimate details of the molecular geometry at the active site.
Schinazi, a viral pharmacologist at the Emory University School of Medicine in Atlanta, and his colleagues report that a buckyball specially tailored to fit into the active site of a key HIV enzyme -- HIV protease -- paralyzes the virus, rendering it noninfectious in human cells grown in the laboratory.
Moreover, these oligonucleotide compounds do not exhibit antisense activity (binding to messenger RNA), but rather directly bind to the RNA component of telomerase at the active site of the enzyme, thereby acting like a conventional pharmaceutical drug.
The three stop-action atomic structures they obtained suggest that the chlorinated molecule winds its way through a narrow channel in the enzyme to the active site, an isolated internal pocket where the reaction occurs.
If you know the topology of the active site, then it should be possible to design chemical agents that fit into the active site and inhibit the enzyme," Monder says.
The firm designs websites for the Miami Heat (the most active site in the NBA) and Disney, along with a number of companies listed in the Fortune 500.
Contract notice: Annual road management for the active site residenzstraE-e.

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