active site

(redirected from Catalytic site)
Also found in: Dictionary, Thesaurus, Encyclopedia.
Related to Catalytic site: active site, induced fit model

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.

You may read more here:

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.

More discussions about active site
References in periodicals archive ?
1] motor: cleavage of ATP at the catalytic site occurs in 1 ms before 40[degrees] substep rotation.
Competitive inhibition is a result of competition between probe substrates and substrates with higher affinity or inhibitors which bind to the catalytic site but not metabolized, like quinidine.
Due to the small size of the nickel nanoparticles (approximately 10 nanometers), which have been distributed homogenously on the surface of the composite graphite, active catalytic sites increase on the surface of the electrode.
SP If you can control the outermost two or three atomic layers of these tubes so that there are no unwanted catalytic sites that form filamentous coke, you've eliminated that problem.
The summation of all mechanisms decreased the number of active catalytic sites.
On the other hand, the high limonene concentrations could interfere with the availability of catalytic sites and the limonene can be adsorbed more easily in active sites.
Iowa State noted that Lin's particles can also be used as a catalyst for the efficient conversion of animals fats to biodiesel via the creation of a mixed oxide catalyst with both acidic and basic catalytic sites.
Also, solid particles suspended in the atmosphere can react with surrounding gases or act as catalytic sites where other substances can conveniently intermingle and react.
Platinum Plus both catalytically activated the oxidation of soot in the engine and exhaust, and provided a constant replenishment of active catalytic sites on the filter surfaces.
Contaminants in water which are adsorbed rather than reacted tend to occlude catalytic sites, eventually reducing chloramine removal efficiencies to the point where thermal reactivation or replacement is necessary.
8 Catalytic Sites inside the Dendrimeric Structure for Homogeneous Catalysis
The Citys DOP, on behalf of the Department of City Planning ( DCP ), is seeking proposals from qualified firms for Consulting Services to conduct a study for the development of a Blueprint to capture the unique history, to identify catalytic sites and projects to spur redevelopment, and to catalogue the communities assets as well as challenges in the neighborhoods of Adair Park, Sylvan Hills, Capitol View, and Capitol View Manor