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.

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.

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References in periodicals archive ?
5-OH of WEL exhibited a high probability of glucuronidation because it was accessible to the catalytic domain of UGTIAs.
Docking and re-docking were performed in order to analyze the main physicochemical and thermodynamically issues of the interaction of 3,5 DCQA with the catalytic domain of HTLV-I IN (Figure 3).
Iodoacetamide Tagging of Critical Cysteine Residues Within the Catalytic Domain of Furin Provides Evidence of Disulfide Bond Location.
1988) and represents the most conserved portion within the catalytic domain.
As calculated by SWISSMODEL workspace, there is a catalytic domain from residues 91 to 352 in goat p70S6K; the quaternary structure is shown in Figure 2.
The truncated catalytic domain of MMP-9 (MMP-9 CD) comprising residues 107-216 and 391-444 was constructed and cloned into a pET-15b vector (Novagen Brand), resulting in expression plasmid pET15b-MMP-9 CD (Jiang et al 2010).
Xyn1B contained one catalytic domain belongs to glycosyl hydrolase family 11 and no dockerin domain was observed although a linker sequence was found in the C terminal of the polypeptide.
The domain structure of Chi-54 gene shows a cellulose binding domain (CBD), chitin binding domain (ChBD), a catalytic domain (CD), and a signal peptide (SP), (Fig 1).
The catalytic domain is referred to as the A-chain of DT (DTA); the remainder is referred to as the B-chain.
Cysteine Residues in the Catalytic Domain of Mammalian Furin Form Disulfide Bonds That are Critical for Catalytic Activity.
The research article, entitled "Structure of the Catalytic Domain of Human Polo-like Kinase 1" was published in the May 22, 2007 issue of Biochemistry.