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Cystathionine-β-synthase, also known as CBS, is an enzyme () that in humans is encoded by the ''CBS'' gene. It catalyzes the first step of the transsulfuration pathway, from homocysteine to cystathionine:〔(【引用サイトリンク】 url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=875 )〕 :L-serine + L-homocysteine L-cystathionine + H2O CBS uses the cofactor pyridoxal-phosphate (PLP) and can be allosterically regulated by effectors such as the ubiquitous cofactor S-adenosyl-L-methionine (adoMet). This enzyme belongs to the family of lyases, to be specific, the hydro-lyases, which cleave carbon-oxygen bonds. CBS is a multidomain enzyme composed of an N-terminal enzymatic domain and two CBS domains. The ''CBS'' gene is the most common locus for mutations associated with homocystinuria. == Nomenclature == The systematic name of this enzyme class is L-serine hydro-lyase (adding homocysteine; L-cystathionine-forming). Other names in common use include: * beta-thionase, * cysteine synthase, * L-serine hydro-lyase (adding homocysteine), * methylcysteine synthase, * serine sulfhydrase, and * serine sulfhydrylase. Methylcysteine synthase was assigned the EC number EC 4.2.1.23 in 1961. A side-reaction of CBS caused this. The EC number EC 4.2.1.23 was deleted in 1972. 〔(EC 4.2.1.23 )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cystathionine beta synthase」の詳細全文を読む スポンサード リンク
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