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 ?
MMP-9 is a zinc-dependent endopeptidase, and holds several representative structural domains: propeptide domain, catalytic domain, hemopexin-like domain and fibronectin II inserts (Rosenblum et al.
Our results demonstrated that the catalytic domain of both enzymes is sufficient for detection.
Iodoacetamide Tagging of Critical Cysteine Residues Within the Catalytic Domain of Furin Provides Evidence of Disulfide Bond Location.
The catalytic domain (CD) of Chi-a strating from 271 base pair and ended with 1668 base pair, in which the mutagenesis was occurred from 127-133 and in 1462-1468 base pairs, after mutagenesis.
Further analysis of yak GAPDH amino acid sequence implied that it contains a complete NAD (P) binding domain in its N-terminal, a complete catalytic domain of sugar transport in its C-terminal (Figure 5).
The cysteine residues are located in the carboxy-terminal half of the enzyme where the catalytic domain is situated (11).
ENB-0040 is a fusion protein that includes the catalytic domain of human tissue non-specific alkaline phosphatase (TNSALP), an immunoglobulin Fc domain and a patented anionic peptide used to target the enzyme to bone.
Some of the dysfunctional FVII variants possess either an Arg 79-to-G1n substitution in the first epidermal growth factor (EGF)-like domain or an Arg 353-to-Gln substitution in the catalytic domain of FVII (7-11).
The study describes the crystal structure of VX-680 bound to the catalytic domain of BCR-ABL containing a mutation that causes Gleevec resistance but is inhibited by VX-680 in vitro.
This revealed previously unknown mutations not only in the tyrosine kinase catalytic domains, but in other functional domains as well," explained Dr.