Open main menu
Home
Random
Recent changes
Special pages
Community portal
Preferences
About Wikipedia
Disclaimers
Incubator escapee wiki
Search
User menu
Talk
Dark mode
Contributions
Create account
Log in
Editing
Active site
(section)
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
===Covalent catalysis=== Many enzymes including [[serine protease]], [[cysteine protease]], [[protein kinase]] and [[phosphatase]] evolved to form transient covalent bonds between them and their substrates to lower the activation energy and allow the reaction to occur. This process can be divided into 2 steps: formation and breakdown. The former step is rate-limit step while the later step is needed to regenerate intact enzyme.<ref name=":1" />{{Rp|158}} '''Nucleophilic catalysis''': This process involves the donation of electrons from the enzyme's [[nucleophile]] to a substrate to form a covalent bond between them during the transition state. The strength of this interaction depends on two aspects.: the ability of the nucleophilic group to donate electrons and the [[electrophile]] to accept them. The former one is mainly affected by the basicity(the ability to donate electron pairs) of the species while the later one is in regard to its [[acid dissociation constant|p''K''<sub>a</sub>]]. Both groups are also affected by their chemical properties such as [[polarizability]], [[electronegativity]] and [[ionization energy|ionization potential]]. Amino acids that can form nucleophile including [[serine]], [[cysteine]], [[aspartate]] and [[glutamine]].{{citation needed|date=June 2024}} '''Electrophilic catalysis''': The mechanism behind this process is exactly same as nucleophilic catalysis except that now amino acids in active site act as [[electrophile]] while substrates are [[nucleophiles]]. This reaction usually requires cofactors as the amino acid side chains are not strong enough in attracting electrons.
Edit summary
(Briefly describe your changes)
By publishing changes, you agree to the
Terms of Use
, and you irrevocably agree to release your contribution under the
CC BY-SA 4.0 License
and the
GFDL
. You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
Cancel
Editing help
(opens in new window)