Which of the following is a cofactor for cystathionine B synthase?
Chr. Chr. CBS uses the cofactor pyridoxal-phosphate (PLP) and can be allosterically regulated by effectors such as the ubiquitous cofactor S-adenosyl-L-methionine (adoMet).
What is the CBS gene mutation?
This form of homocystinuria is caused by a genetic mutation in the CBS gene , which leads to low levels or absence of an enzyme called cystathionine beta-synthase (CBS). When CBS is absent or not working right, homocysteine and other toxic chemicals build up in the blood and urine.
Why is homocysteine test done?
A homocysteine test may be used to: Find out if you have deficiency in vitamin B12, B6, or folic acid. Help diagnose homocystinuria, a rare, inherited disorder that prevents the body from breaking down certain proteins. It can cause serious health problems and usually starts in early childhood.
What is homocysteine plasma?
Homocysteine is an amino acid. Vitamins B12, B6 and folate break down homocysteine to create other chemicals your body needs. High homocysteine levels may mean you have a vitamin deficiency. Without treatment, elevated homocysteine increases your risks for dementia, heart disease and stroke.
Can homocysteine be detected in urine?
Homocystinuria is a disorder of methionine metabolism, leading to an abnormal accumulation of homocysteine and its metabolites (homocystine, homocysteine-cysteine complex, and others) in blood and urine. Normally, these metabolites are not found in appreciable quantities in blood or urine.
What is the function of cystathionine beta synthase?
Cystathionine β -synthase (CBS) regulates homocysteine metabolism and contributes to hydrogen sulfide (H 2 S) biosynthesis through which it plays multifunctional roles in the regulation of cellular energetics, redox status, DNA methylation, and protein modification.
Is cystathionine-β-synthase a rate limiting enzyme?
This article has been cited by other articles in PMC. Cystathionine-β-synthase (CBS), the first (and rate-limiting) enzyme in the transsulfuration pathway, is an important mammalian enzyme in health and disease.
How does cystathionine beta-synthase convert Hcy to GSH?
Cystathionine beta-synthase (CBS) converts HCY to GSH via the transsulfuration pathway with vitamin B6 as cofactor [53–55] ( Fig. 3.2 ). The tripeptide GSH is the main antioxidant and detoxification molecule. Keeping the balance between methylation and transsulfuration depends on methionine levels and allosteric activation of CBS by SAM.
Is cystathionine β-synthase downregulated in hepatocellular carcinoma?
Kim J., Hong S. J., Park J. H., et al. Expression of cystathionine β-synthase is downregulated in hepatocellular carcinoma and associated with poor prognosis. Oncology Reports. 2009;21(6):1449–1454. doi: 10.3892/or_00000373.