Enzymes for Producing Homocysteine Assay Kit

Homocysteine, a sulfhydryl-containing amino acid, is an intermediate product in the normal biosynthesis of the amino acids methionine and cysteine. It is an amino acid produced via demethylation of dietary methionine, which is abundant in animal protein. It is present in plasma in four different forms: around 1% circulates as free thiol, 70–80% remains disulfide-bound to plasma proteins, mainly albumin and 20–30% combines with itself to form the dimer homocysteine or with other thiols. Homocysteine is a key determinant of the methylation cycle.

It has been proved that high levels of homocysteine are associated with multiple diseases such as hyperhomocysteinemia, CNS neurodegenerative disorders, and cardiovascular disease. Homocysteinylated proteins may also act as autoantigens, triggering arterial inflammation and atherosclerosis. Elevated plasma homocysteine concentration is a clinical biomarker for increased risk of cardiovascular disease, ischemic stroke, and myocardial infarction.

Homocysteine assay kit is used to quantify total homocysteine in biological fluids such as plasma and serum. The assay is based on the reduction of homocysteine disulfides to free homocysteine, which is cleaved by a homocysteine-selective enzyme, generating an intermediate product.

Creative Enzymes provides raw materials, such as homocysteine methyltransferase (EC 2.1.1.10), S-adenosyl-L-homocysteine hydrolase (EC 3.3.1.1), adenosine deaminase (EC 3.5.4.4), S-adenosylmethionine synthetase (EC 2.5.1.6), for the production of homocysteine assay kits.

Homocysteine methyltransferase (EC 2.1.1.10)  is an enzyme that catalyzes S-methylmethionine and L-homocysteine into L-methionine. This enzyme belongs to the family of transferases, specifically those transferring one-carbon group methyltransferases. S-adenosyl-L-homocysteine hydrolase (EC 3.3.1.1, AdoHcyase) is an enzyme of the activated methyl cycle, responsible for the reversible hydration of S-adenosyl-L-homocysteine into adenosine and homocysteine. AdoHcyase is significantly associated with adenosine deaminase deficiency, which classically manifests in severe combine immunodeficiency (SCID). Adenosine deaminase (EC 3.5.4.4, ADA) is a widely expressed metabolic enzyme with the highest levels observed in lymphatic tissues, especially the thymus and gastrointestinal tract. Together with purine nucleoside phosphorylase, it forms an important part of the purine salvage pathway and is responsible for deaminating adenosine and 2'deoxyadenosine to produce inosine and 2'deoxyinosine. S-adenosylmethionine synthetase (EC 2.5.1.6) is an enzyme that creates S-adenosylmethionine by reacting methionine and ATP. AdoMet is a methyl donor for transmethylation. It gives away its methyl group and is also the propylamino donor in polyamine biosynthesis. S-adenosylmethionine synthesis can be considered the rate-limiting step of the methionine cycle.

Reference

1. Ganguly P, Alam S. Role of homocysteine in the development of cardiovascular disease[J]. Nutrition Journal, 2015, 14(1):1-10.