The enzyme argininosuccinate lyase (EC 4.3.2.1, ASL, argininosuccinase; systematic name 2-(N ω-L-arginino)succinate arginine-lyase (fumarate-forming)) catalyzes the reversible breakdown of argininosuccinate:
Serine hydroxymethyltransferase (SHMT) is a pyridoxal phosphate (PLP) (Vitamin B6) dependent enzyme (EC 2.1.2.1) which plays an important role in cellular one-carbon pathways by catalyzing the reversible, simultaneous conversions of L-serine to glycine and tetrahydrofolate (THF) to 5,10-Methylenetetrahydrofolate (5,10-CH2-THF). This reaction provides the largest part of the one-carbon units available to the cell.
Histidine ammonia-lyase is an enzyme that in humans is encoded by the HAL gene. It converts histidine into ammonia and urocanic acid. Its systematic name is L-histidine ammonia-lyase (urocanate-forming).
The enzyme cystathionine γ-lyase (EC 4.4.1.1, CTH or CSE; also cystathionase; systematic name L-cystathionine cysteine-lyase (deaminating; 2-oxobutanoate-forming)) breaks down cystathionine into cysteine, 2-oxobutanoate (α-ketobutyrate), and ammonia:
5-Formiminotetrahydrofolate is an intermediate in the catabolism of histidine. It is produced by glutamate formimidoyltransferase and then converted into 5,10-methenyltetrahydrofolate by formiminotransferase cyclodeaminase.
Glutamate formimidoyltransferase is a methyltransferase enzyme which uses tetrahydrofolate as part of histidine catabolism. It catalyses two reactions:
The enzyme ornithine cyclodeaminase catalyzes the chemical reaction
The enzyme phenylalanine ammonia lyase (EC 4.3.1.24) catalyzes the conversion of L-phenylalanine to ammonia and trans-cinnamic acid.:
In enzymology, a glycine formimidoyltransferase is an enzyme that catalyzes the chemical reaction
Isocitrate lyase, or ICL, is an enzyme in the glyoxylate cycle that catalyzes the cleavage of isocitrate to succinate and glyoxylate. Together with malate synthase, it bypasses the two decarboxylation steps of the tricarboxylic acid cycle and is used by bacteria, fungi, and plants.
The enzyme chorismate synthase catalyzes the chemical reaction
In enzymology, an amidase (EC 3.5.1.4, acylamidase, acylase (misleading), amidohydrolase (ambiguous), deaminase (ambiguous), fatty acylamidase, N-acetylaminohydrolase (ambiguous)) is an enzyme that catalyzes the hydrolysis of an amide. In this way, the two substrates of this enzyme are an amide and H2O, whereas its two products are monocarboxylate and NH3.
In enzymology, a methenyltetrahydrofolate cyclohydrolase (EC 3.5.4.9) is an enzyme that catalyzes the chemical reaction
Bifunctional methylenetetrahydrofolate dehydrogenase/cyclohydrolase, mitochondrial is an enzyme that in humans is encoded by the MTHFD2 gene.
5,10-Methenyltetrahydrofolate (5,10-CH=THF) is a form of tetrahydrofolate that is an intermediate in metabolism. 5,10-CH=THF is a coenzyme that accepts and donates methenyl (CH=) groups.
The glycine cleavage system (GCS) is also known as the glycine decarboxylase complex or GDC. The system is a series of enzymes that are triggered in response to high concentrations of the amino acid glycine. The same set of enzymes is sometimes referred to as glycine synthase when it runs in the reverse direction to form glycine. The glycine cleavage system is composed of four proteins: the T-protein, P-protein, L-protein, and H-protein. They do not form a stable complex, so it is more appropriate to call it a "system" instead of a "complex". The H-protein is responsible for interacting with the three other proteins and acts as a shuttle for some of the intermediate products in glycine decarboxylation. In both animals and plants, the glycine cleavage system is loosely attached to the inner membrane of the mitochondria. Mutations in this enzymatic system are linked with glycine encephalopathy.
In molecular biology, enzymes containing the cyclodeaminase domain function in channeling one-carbon units to the folate pool. In most cases, this domain acts as a formimidoyltetrahydrofolate cyclodeaminase, which catalyses the cyclisation of formimidoyltetrahydrofolate to methenyltetrahydrofolate as shown in reaction (1). In the methylotrophic bacterium Methylobacterium extorquens, however, it acts as a methenyltetrahydrofolate cyclohydrolase, which catalyses the interconversion of formyltetrahydrofolate and methylenetetrahydrofolate, as shown in reaction (2).
Tyrosine ammonia lyase (EC 4.3.1.23, L-tyrosine ammonia-lyase, TAL or Tyrase) is an enzyme in the natural phenols biosynthesis pathway. It transforms L-tyrosine into p-coumaric acid.
Phenylalanine/tyrosine ammonia-lyase (EC 4.3.1.25, PTAL, bifunctional PAL) is an enzyme with systematic name L-phenylalanine(or L-tyrosine):trans-cinnamate(or trans-p-hydroxycinnamate) ammonia-lyase. This enzyme catalyses the following chemical reaction
L-lysine cyclodeaminase (EC 4.3.1.28, rapL (gene), fkbL (gene), tubZ (gene), visC (gene)) is an enzyme with systematic name L-lysine ammonia-lyase (cyclizing; ammonia-forming). This enzyme catalyses the following chemical reaction
