In biochemistry, a ribonucleotide is a nucleotide containing ribose as its pentose component. It is considered a molecular precursor of nucleic acids. Nucleotides are the basic building blocks of DNA and RNA. Ribonucleotides themselves are basic monomeric building blocks for RNA. Deoxyribonucleotides, formed by reducing ribonucleotides with the enzyme ribonucleotide reductase (RNR), are essential building blocks for DNA. There are several differences between DNA deoxyribonucleotides and RNA ribonucleotides. Successive nucleotides are linked together via phosphodiester bonds.
In molecular biology, biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined to form macromolecules. This process often consists of metabolic pathways. Some of these biosynthetic pathways are located within a single cellular organelle, while others involve enzymes that are located within multiple cellular organelles. Examples of these biosynthetic pathways include the production of lipid membrane components and nucleotides. Biosynthesis is usually synonymous with anabolism.
Glycoside hydrolases catalyze the hydrolysis of glycosidic bonds in complex sugars. They are extremely common enzymes with roles in nature including degradation of biomass such as cellulose (cellulase), hemicellulose, and starch (amylase), in anti-bacterial defense strategies, in pathogenesis mechanisms and in normal cellular function. Together with glycosyltransferases, glycosidases form the major catalytic machinery for the synthesis and breakage of glycosidic bonds.
Phosphoribosylformylglycinamidine cyclo-ligase is the fifth enzyme in the de novo synthesis of purine nucleotides. It catalyzes the reaction to form 5-aminoimidazole ribotide (AIR) from formylglycinamidine-ribonucleotide FGAM. This reaction closes the ring and produces a 5-membered imidazole ring of the purine nucleus (AIR):
Purine metabolism refers to the metabolic pathways to synthesize and break down purines that are present in many organisms.
Guanosine monophosphate synthetase, also known as GMPS is an enzyme that converts xanthosine monophosphate to guanosine monophosphate.
In molecular biology, adenylosuccinate synthase is an enzyme that plays an important role in purine biosynthesis, by catalysing the guanosine triphosphate (GTP)-dependent conversion of inosine monophosphate (IMP) and aspartic acid to guanosine diphosphate (GDP), phosphate and N(6)-(1,2-dicarboxyethyl)-AMP. Adenylosuccinate synthetase has been characterised from various sources ranging from Escherichia coli to vertebrate tissues. In vertebrates, two isozymes are present: one involved in purine biosynthesis and the other in the purine nucleotide cycle.
Amidophosphoribosyltransferase (ATase), also known as glutamine phosphoribosylpyrophosphate amidotransferase (GPAT), is an enzyme responsible for catalyzing the conversion of 5-phosphoribosyl-1-pyrophosphate (PRPP) into 5-phosphoribosyl-1-amine (PRA), using the amine group from a glutamine side-chain. This is the committing step in de novo purine synthesis. In humans it is encoded by the PPAT gene. ATase is a member of the purine/pyrimidine phosphoribosyltransferase family.
Bifunctional purine biosynthesis protein PURH is a protein that in humans is encoded by the ATIC gene.
In enzymology, a 5-(carboxyamino)imidazole ribonucleotide mutase is an enzyme that catalyzes the chemical reaction
In enzymology, a phosphoribosylaminoimidazolecarboxamide formyltransferase, also known by the shorter name AICAR transformylase, is an enzyme that catalyzes the chemical reaction
In enzymology, a 5-(carboxyamino)imidazole ribonucleotide synthase (EC 6.3.4.18) is an enzyme that catalyzes the chemical reaction
Phosphoribosylamine—glycine ligase, also known as glycinamide ribonucleotide synthetase (GARS), (EC 6.3.4.13) is an enzyme that catalyzes the chemical reaction
In molecular biology, the protein domain SAICAR synthase is an enzyme which catalyses a reaction to create SAICAR. In enzymology, this enzyme is also known as phosphoribosylaminoimidazolesuccinocarboxamide synthase. It is an enzyme that catalyzes the chemical reaction
In enzymology, a phosphoribosylformylglycinamidine synthase (EC 6.3.5.3) is an enzyme that catalyzes the chemical reaction
In enzymology, a hydroxyisourate hydrolase (EC 3.5.2.17) is an enzyme that catalyzes the chemical reaction
In enzymology, a phosphoribosyl-AMP cyclohydrolase (EC 3.5.4.19) is an enzyme that catalyzes the chemical reaction
In enzymology, an anthranilate phosphoribosyltransferase is an enzyme that catalyzes the chemical reaction
In enzymology, an ATP phosphoribosyltransferase is an enzyme that catalyzes the chemical reaction
Phosphoribosylglycinamide formyltransferase (EC 2.1.2.2, 2-amino-N-ribosylacetamide 5'-phosphate transformylase, GAR formyltransferase, GAR transformylase, glycinamide ribonucleotide transformylase, GAR TFase, 5,10-methenyltetrahydrofolate:2-amino-N-ribosylacetamide ribonucleotide transformylase) is an enzyme with systematic name 10-formyltetrahydrofolate:5'-phosphoribosylglycinamide N-formyltransferase. This enzyme catalyses the following chemical reaction
