Coenzyme A (CoA, SHCoA, CoASH) is a coenzyme, notable for its role in the synthesis and oxidation of fatty acids, and the oxidation of pyruvate in the citric acid cycle. All genomes sequenced to date encode enzymes that use coenzyme A as a substrate, and around 4% of cellular enzymes use it (or a thioester) as a substrate. In humans, CoA biosynthesis requires cysteine, pantothenate (vitamin B5), and adenosine triphosphate (ATP).
Pyridoxal phosphate (PLP, pyridoxal 5'-phosphate, P5P), the active form of vitamin B6, is a coenzyme in a variety of enzymatic reactions. The International Union of Biochemistry and Molecular Biology has catalogued more than 140 PLP-dependent activities, corresponding to ~4% of all classified activities. The versatility of PLP arises from its ability to covalently bind the substrate, and then to act as an electrophilic catalyst, thereby stabilizing different types of carbanionic reaction intermediates.
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.
Phytomenadione, also known as vitamin K1 or phylloquinone, is a vitamin found in food and used as a dietary supplement. It is on the World Health Organization's List of Essential Medicines.
The crotonase family comprises mechanistically diverse proteins that share a conserved trimeric quaternary structure, the core of which consists of 4 turns of a (beta/beta/alpha)n superhelix.
Isochorismate synthase ( EC 5.4.4.2) is an isomerase enzyme that catalyzes the first step in the biosynthesis of vitamin K2 (menaquinone) in Escherichia coli.
In enzymology, an aminodeoxychorismate synthase is an enzyme that catalyzes the chemical reaction
o-Succinylbenzoate—CoA ligase, encoded from the menE gene in Escherichia coli, catalyzes the fifth reaction in the synthesis of menaquinone. This pathway is called 1, 4-dihydroxy-2-naphthoate biosynthesis I. Vitamin K is a quinone that serves as an electron transporter during anaerobic respiration. This process of anaerobic respiration allows the bacteria to generate the energy required to survive.
The enzyme chorismate synthase catalyzes the chemical reaction
In enzymology, a [acyl-carrier-protein] S-acetyltransferase is an enzyme that catalyzes the reversible chemical reaction
In enzymology, a [acyl-carrier-protein] S-malonyltransferase is an enzyme that catalyzes the chemical reaction
2-Succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate synthase, also known as SHCHC synthase is encoded by the menH gene in Escherichia coli and functions in the synthesis of vitamin K. The specific step in the synthetic pathway that SHCHC synthase catalyzes is the conversion of 5-enolpyruvoyl-6-hydroxy-2-succinylcyclohex-3-ene-1-carboxylate to (1R,6R)-6-hydroxy-2-succinylcyclohexa-2,4-diene-1-carboxylate and pyruvate.
Cobalamin biosynthesis is the process by which bacteria and archea make cobalamin, vitamin B12. Many steps are involved in converting aminolevulinic acid via uroporphyrinogen III and adenosylcobyric acid to the final forms in which it is used by enzymes in both the producing organisms and other species, including humans who acquire it through their diet.
Demethylmenaquinone methyltransferase is an enzyme with systematic name S-adenosyl-L-methionine:demethylmenaquinone methyltransferase. This enzyme catalyses the following chemical reaction
In enzymology, SEPHCHC synthase (EC EC 2.2.1.9), encoded by menD gene in E. coli, is an enzyme that catalyzes the second step of menaquinone (vitamin K2) biosynthesis. The two substrates of this enzyme are 2-oxoglutarate and isochorismate. The products of this enzyme are 5-enolpyruvoyl-6-hydroxy-2-succinyl-cyclohex-3-ene-1-carboxylate and CO2. It belongs to the transferase family.
1-4-dihydroxy-2-napthoate (DHNA) polyprenyltransferase (EC 2.5.1.74)is an enzyme that catalyzes the chemical reaction: all-trans-nonaprenyl diphosphate + 1-4-dihydroxy-2-napthoate + H+ demethylmenaquinol-9 + diphosphate + carbon dioxide
The enzyme 1,4-dihydroxy-2-naphthoyl-CoA hydrolase (EC 3.1.2.28; systematic name 1,4-dihydroxy-2-naphthoyl-CoA hydrolase) catalyses the following reaction:
o-Succinylbenzoate synthase (OSBS) (EC 4.2.1.113) is an enzyme encoded by the menC gene in E.coli, and catalyzes the dehydration of 2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate (SHCHC) to form 4-(2'-carboxyphenyl)-4-oxobutyrate, also called o-succinylbenzoate or OSB, hence the name of the enzyme. This reaction is the fourth step in the menaquinone biosynthetic pathway, which is used by bacteria to synthesize menaquinone, also known as vitamin K2.
Ketoacyl synthases (KSs) catalyze the condensation reaction of acyl-CoA or acyl-acyl ACP with malonyl-CoA to form 3-ketoacyl-CoA or with malonyl-ACP to form 3-ketoacyl-ACP. This reaction is a key step in the fatty acid synthesis cycle, as the resulting acyl chain is two carbon atoms longer than before. KSs exist as individual enzymes, as they do in type II fatty acid synthesis and type II polyketide synthesis, or as domains in large multidomain enzymes, such as type I fatty acid synthases (FASs) and polyketide synthases (PKSs). KSs are divided into five families: KS1, KS2, KS3, KS4, and KS5.
Coenzyme Q5, methyltransferase, more commonly known as COQ5, is an enzyme involved in the electron transport chain. COQ5 is located within the mitochondrial matrix and is a part of the biosynthesis of ubiquinone.
