Pterin is a heterocyclic compound composed of a pteridine ring system, with a "keto group" and an amino group on positions 4 and 2 respectively. It is structurally related to the parent bicyclic heterocycle called pteridine. Pterins, as a group, are compounds related to pterin with additional substituents. Pterin itself is of no biological significance.
Methionine synthase also known as MS, MeSe, MTR is responsible for the regeneration of methionine from homocysteine. In humans it is encoded by the MTR gene (5-methyltetrahydrofolate-homocysteine methyltransferase). Methionine synthase forms part of the S-adenosylmethionine (SAMe) biosynthesis and regeneration cycle, and is the enzyme responsible for linking the cycle to one-carbon metabolism via the folate cycle. There are two primary forms of this enzyme, the Vitamin B12 (cobalamin)-dependent (MetH) and independent (MetE) forms, although minimal core methionine synthases that do not fit cleanly into either category have also been described in some anaerobic bacteria. The two dominant forms of the enzymes appear to be evolutionary independent and rely on considerably different chemical mechanisms. Mammals and other higher eukaryotes express only the cobalamin-dependent form. In contrast, the distribution of the two forms in Archaeplastida (plants and algae) is more complex. Plants exclusively possess the cobalamin-independent form, while algae have either one of the two, depending on species. Many different microorganisms express both the cobalamin-dependent and cobalamin-independent forms.
Molybdopterins are a class of cofactors found in most molybdenum-containing and all tungsten-containing enzymes. Synonyms for molybdopterin are: MPT and pyranopterin-dithiolate. The nomenclature for this biomolecule can be confusing: Molybdopterin itself contains no molybdenum; rather, this is the name of the ligand that will bind the active metal. After molybdopterin is eventually complexed with molybdenum, the complete ligand is usually called molybdenum cofactor.
Biotin synthase (BioB) is an enzyme that catalyzes the conversion of dethiobiotin (DTB) to biotin; this is the final step in the biotin biosynthetic pathway. Biotin, also known as vitamin B7, is a cofactor used in carboxylation, decarboxylation, and transcarboxylation reactions in many organisms including humans. Biotin synthase is an S-Adenosylmethionine (SAM) dependent enzyme that employs a radical mechanism to thiolate dethiobiotin, thus converting it to biotin.
Molybdenum cofactor biosynthesis protein 1 is a protein that in humans and other animals, fungi, and cellular slime molds, is encoded by the MOCS1 gene.
Molybdenum cofactor synthesis protein 2A and molybdenum cofactor synthesis protein 2B are a pair of proteins that in humans are encoded from the same MOCS2 gene. These two proteins dimerize to form molybdopterin synthase.
5′-Phosphoribosyl-5-aminoimidazole is a biochemical intermediate in the formation of purine nucleotides via inosine-5-monophosphate, and hence is a building block for DNA and RNA. The vitamins thiamine and cobalamin also contain fragments derived from AIR. It is an intermediate in the adenine pathway and is synthesized from 5′-phosphoribosylformylglycinamidine by AIR synthetase.
Molybdopterin synthase (EC 2.8.1.12, MPT synthase) is an enzyme required to synthesize molybdopterin (MPT) from precursor Z (now known as cyclic pyranopterin monophosphate). Molydopterin is subsequently complexed with molybdenum to form molybdenum cofactor (MoCo). MPT synthase catalyses the following chemical reaction:
Radical SAM is a designation for a superfamily of enzymes that use a [4Fe-4S]+ cluster to reductively cleave S-adenosyl-L-methionine (SAM) to generate a radical, usually a 5′-deoxyadenosyl radical (5'-dAdo), as a critical intermediate. These enzymes utilize this radical intermediate to perform diverse transformations, often to functionalize unactivated C-H bonds. Radical SAM enzymes are involved in cofactor biosynthesis, enzyme activation, peptide modification, post-transcriptional and post-translational modifications, metalloprotein cluster formation, tRNA modification, lipid metabolism, biosynthesis of antibiotics and natural products etc. The vast majority of known radical SAM enzymes belong to the radical SAM superfamily, and have a cysteine-rich motif that matches or resembles CxxxCxxC. rSAMs comprise the largest superfamily of metal-containing enzymes.
Quinolinate synthase (EC 2.5.1.72, NadA, QS, quinolinate synthetase) is an enzyme with systematic name glycerone phosphate:iminosuccinate alkyltransferase (cyclizing). This enzyme catalyses the following chemical reaction
Molybdenum cofactor cytidylyltransferase is an enzyme with systematic name CTP:molybdenum cofactor cytidylyltransferase. This enzyme catalyses the following chemical reaction:
Molybdenum cofactor guanylyltransferase is an enzyme with systematic name GTP:molybdenum cofactor guanylyltransferase. This enzyme catalyses the following chemical reaction:
Molybdopterin-synthase adenylyltransferase is an enzyme with systematic name ATP:molybdopterin-synthase adenylyltransferase. This enzyme catalyses the following chemical reaction
Molybdenum cofactor sulfurtransferase (EC 2.8.1.9, molybdenum cofactor sulfurase, ABA3, MoCo sulfurase, MoCo sulfurtransferase) is an enzyme with systematic name L-cysteine:molybdenum cofactor sulfurtransferase. This enzyme catalyses the following chemical reaction
Molybdopterin synthase sulfurtransferase is an enzyme with systematic name persulfurated L-cysteine desulfurase:(molybdopterin-synthase sulfur-carrier protein)-Gly-Gly sulfurtransferase. This enzyme catalyses the following chemical reaction
Molybdopterin molybdotransferase is an enzyme with systematic name adenylyl-molybdopterin:molybdate molybdate transferase (AMP-forming). This enzyme catalyses the following chemical reaction
3′,5′-cyclic-AMP phosphodiesterase (EC 3.1.4.53, cAMP-specific phosphodiesterase, cAMP-specific PDE, PDE1, PDE2A, PDE2B, PDE4, PDE7, PDE8, PDEB1, PDEB2) is an enzyme with systematic name 3′,5′-cyclic-AMP 5′-nucleotidohydrolase. It catalyses the following reaction
Squire Booker is an American biochemist at Penn State University. Booker directs an interdisciplinary chemistry research program related to fields of biochemistry, enzymology, protein chemistry, natural product biosynthesis, and mechanisms of radical dependent enzymes. He is an associate editor for the American Chemical Society Biochemistry Journal, is a Hughes Medical Institute Investigator, and an Eberly Distinguished Chair in Science at Penn State University.
Fosdenopterin, sold under the brand name Nulibry, is a medication used to reduce the risk of death due to a rare genetic disease known as molybdenum cofactor deficiency type A.
Kenichi Yokoyama is an enzymologist, chemical biologist, and natural product biochemist originally from Tokyo, Japan. He is an Associate Professor of Biochemistry at Duke University School of Medicine. In 2019, Yokoyama was awarded the Pfizer Award in Enzyme Chemistry from the American Chemical Society.
