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Nucleotidyltransferases are
Nucleotidyltransferases are transferase
A transferase is any one of a class of enzymes that catalyse the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor). They are involved in hundreds o ...
enzymes of phosphorus-containing groups, e.g., substituent
A substituent is one or a group of atoms that replaces (one or more) atoms, thereby becoming a moiety in the resultant (new) molecule. (In organic chemistry and biochemistry, the terms ''substituent'' and ''functional group'', as well as '' side ...
s of nucleotidylic acids or simply nucleoside monophosphate
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules with ...
s. The general reaction of transferring a nucleoside monophosphate moiety from A to B, can be written as:
:A-P-N + B A + B-P-N
For example, in the case of polymerases, A is pyrophosphate and B is the nascent polynucleotide.
They are classified under EC number 2.7.7 and they can be categorised into:
# Uridylyltransferases, which transfer uridylyl
Uridine monophosphate (UMP), also known as 5′-uridylic acid (conjugate base uridylate), is a nucleotide that is used as a monomer in RNA. It is an ester of phosphoric acid with the nucleoside uridine. UMP consists of the phosphate group, ...
- groups
#Adenylyltransferase
Molybdopterin-synthase adenylyltransferase (, ''MoeB'', ''adenylyltransferase and sulfurtransferase MOCS3'') is an enzyme with systematic name ''ATP:molybdopterin-synthase adenylyltransferase''. This enzyme catalyses the following chemical reactio ...
s, which transfer adenylyl
Adenosine monophosphate (AMP), also known as 5'-adenylic acid, is a nucleotide. AMP consists of a phosphate group, the sugar ribose, and the nucleobase adenine; it is an ester of phosphoric acid and the nucleoside adenosine. As a substitu ...
- groups
#Guanylyltransferase Guanylyl transferases are enzymes that transfer a guanosine mono phosphate group, usually from GTP to another molecule, releasing pyrophosphate. Many eukaryotic guanylyl transferases are capping enzymes that catalyze the formation of the 5' cap in ...
s, which transfer guanylyl- groups
# Cytitidylyltransferases, which transfer cytidylyl- groups
# Thymidylyltransferases, which transfer thymidylyl- groups
Role in metabolism
Many metabolic enzymes are modified by nucleotidyltransferases. The attachment of an AMP (adenylylation) or UMP (uridylylation) can activate or inactivate an enzyme or change its specificity (see figure). These modifications can lead to intricate regulatory networks that can finely tune enzymatic activities so that only the needed compounds are made (here: glutamine).Role in DNA repair mechanisms
Nucleotidyl transferase is a component of the repair pathway for single nucleotidebase excision repair
Base excision repair (BER) is a cellular mechanism, studied in the fields of biochemistry and genetics, that repairs damaged DNA throughout the cell cycle. It is responsible primarily for removing small, non-helix-distorting base lesions from ...
. This repair mechanism begins when a single nucleotide is recognized by DNA glycosylase as incorrectly matched or has been mutated in some way (UV light, chemical mutagen, etc.), and is removed. Later, a nucleotidyl transferase is used to fill in the gap with the correct base, using the template strand as the reference.
References
External links
* Transferases * {{2.7-enzyme-stub