In biochemistry, a ligase is an enzyme that can catalyze the joining (ligation) of two molecules by forming a new chemical bond. This is typically via hydrolysis of a small pendant chemical group on one of the molecules, typically resulting in the formation of new C-O, C-S, or C-N bonds. For example, DNA ligase can join two complementary fragments of nucleic acid by forming phosphodiester bonds, and repair single stranded breaks that arise in double stranded DNA during replication.
The enzyme citrate synthase E.C. 2.3.3.1 ] exists in nearly all living cells and stands as a pace-making enzyme in the first step of the citric acid cycle. Citrate synthase is localized within eukaryotic cells in the mitochondrial matrix, but is encoded by nuclear DNA rather than mitochondrial. It is synthesized using cytoplasmic ribosomes, then transported into the mitochondrial matrix.
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:
In enzymology, a 2-oxobutyrate synthase (EC 1.2.7.2) is an enzyme that catalyzes the chemical reaction
In enzymology, a 3-methyl-2-oxobutanoate dehydrogenase (ferredoxin) (EC 1.2.7.7) is an enzyme that catalyzes the chemical reaction
In enzymology, a 3-methyl-2-oxobutanoate hydroxymethyltransferase (EC 2.1.2.11) is an enzyme that catalyzes the chemical reaction
In enzymology, a 2-isopropylmalate synthase (EC 2.3.3.13) is an enzyme that catalyzes the chemical reaction
In enzymology, a 3-ethylmalate synthase (EC 2.3.3.7) is an enzyme that catalyzes the chemical reaction
In enzymology, a 3-propylmalate synthase (EC 2.3.3.12) is an enzyme that catalyzes the chemical reaction
In enzymology, a 6-methylsalicylic-acid synthase (EC 2.3.1.165) is a polyketide synthase that catalyzes the chemical reaction
In enzymology, a citrate (Re)-synthase (EC 2.3.3.3) is an enzyme that catalyzes the chemical reaction
In enzymology, a decylhomocitrate synthase (EC 2.3.3.4) is an enzyme that catalyzes the chemical reaction
In enzymology, a glycine C-acetyltransferase is an enzyme that catalyzes the chemical reaction:
In enzymology, a homocitrate synthase (EC 2.3.3.14) is an enzyme that catalyzes the chemical reaction
In molecular biology, hydroxymethylglutaryl-CoA synthase or HMG-CoA synthase EC 2.3.3.10 is an enzyme which catalyzes the reaction in which acetyl-CoA condenses with acetoacetyl-CoA to form 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA). This reaction comprises the second step in the mevalonate-dependent isoprenoid biosynthesis pathway. HMG-CoA is an intermediate in both cholesterol synthesis and ketogenesis. This reaction is overactivated in patients with diabetes mellitus type 1 if left untreated, due to prolonged insulin deficiency and the exhaustion of substrates for gluconeogenesis and the TCA cycle, notably oxaloacetate. This results in shunting of excess acetyl-CoA into the ketone synthesis pathway via HMG-CoA, leading to the development of diabetic ketoacidosis.
In enzymology, lovastatin nonaketide synthase (EC 2.3.1.161) is an enzyme that catalyzes the chemical reaction
In enzymology, a malate synthase (EC 2.3.3.9) is an enzyme that catalyzes the chemical reaction
In enzymology, a N-acetylneuraminate synthase (EC 2.5.1.56) is an enzyme that catalyzes the chemical reaction
In enzymology, a [3-methyl-2-oxobutanoate dehydrogenase (acetyl-transferring)] is an enzyme that catalyzes the chemical reaction
(R)-citramalate synthase (EC 2.3.1.182, CimA) is an enzyme. This enzyme catalyses the following chemical reaction
