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.
Farlex Partner Medical Dictionary © Farlex 2012

active site

The part of an enzyme at which catalysis of the substrate occurs.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

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.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

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.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

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.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
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.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

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
This content is provided by iMedix and is subject to iMedix Terms. The Questions and Answers are not endorsed or recommended and are made available by patients, not doctors.
References in periodicals archive ?
Fig 2B shows the 3D diagram of interactions of Blasticidin S hydrochloride at the LGMN catalytic site.
Boyer, "Catalytic site forms and controls in ATP synthase catalysis," Biochimica et Biophysica Acta, vol.
Possible favorable interactions (of minimum binding energy and hydrogen bonding) with amino acids at possible target sites (PAS and catalytic site) were determined by Lamarckian genetic algorithm (LGA, method which is the most efficient, reliable, and successful) and Genetic Algorithm.
The mechanism indicates that the nitrile dynamically occupies some catalytic sites. Such an occupancy certainly reduces the real catalyst concentration participating to activate hydro gen for C=C hydrogenation.
The amino acid alignments of catalytic sites of the related PLBs is shown in Fig.
The peculiar feature of lipases is the presence of a/AY hydrolase fold in the N-terminal domain which contains a buried active site in the form of a catalytic triad which is similar to the catalytic site of chemotrypsin, trypsin, serine proteases and other esterases (Brzozowski et al., 1991; Brady et al., 1990; Winkler et al., 1990; Schrag et al., 1991; Lowe, 1992; Beer et al., 1996).
The open conformation of TIM permits easier access to the catalytic site. The high conservation of the TIM catalytic site, and its centrality in cancer, suggests that a molecule targeted to that site might provide a therapy that could escape some drug resistance mechanisms.
Dihydrospinochalcone-A showed calculated affinity with eNOS in the Cl binding pockets, near the catalytic site; Trp449, Trp447 and His373 through aromatic and [pi]--[pi] interactions, also His463 and Arg367 are the residues that make hydrogen bonds with the carbonyl and hydroxyl groups.
Primarily as a result of the increase in [K.sub.m], the efficiencies of these substrates decreased approximately two- to sixfold for proteinases such as trypsin and chymotrypsin, which have a relatively accessible catalytic site. Efficiency of cleavage of substrates by thrombin decreased by ~3-and 20-fold when a substrate was linked to PEG, possibly reflecting the greater steric hindrance of the thrombin active site (32) or its extended substrate specificity (7,12-14).
"There had been a lot of confusion about how DNA enters the polymerase and how the DNA is oriented relative to the catalytic site," notes Stillman.
38) A structural comparison of CM-RNase [T.sub.1]x2'-GMP with intact RNase [T.sub.1]x2'-GMP revealed that the CM group is present in the catalytic site and prevents the phosphate of nucleotide from coming into the phosphate binding site.

Full browser ?