Isoforms of human serum biotinidase.
Isoforms of human serum biotinidase.
复制标题
人血清生物素酶的亚型。
DOI：
10.1016/0009-8981(91)90146-4
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Wolf,B
中科院分区：
文献类型：
--
作者：
Hart,PS;Hymes,J;Wolf,B
In humans there are four known biotin-dependent carboxylases, pyruvate carboxylase(EC 6.4. 1.1), acetyl CoA carboxylase(EC 6.4. 1.2) propionyl CoA carboxylase (EC 6.4. 1.3) and P-methylcrotonyl CoA carboxylase (EC 6.4. 1.4) that are involved in various metabolic pathways, including gluconeogenesis, amino acid catabolism and fatty acid synthesis [l]. Proteolytic degradation of these carboxylases results in the formation of biocytin, eN-(d-biotinyl)-L-lysine. The enzyme biotinidase (EC 3.5. 1.12) catalyzes the cleavage of biotin from biotinyl-peptides and from biocytin, resulting in the recycling of the vitamin [2-41. Late-onset multiple carboxylase deficiency, an autosomal recessively inherited disorder, is due to a deficiency of biotinidase activity [5].Biotinidase is composed of a single polypeptide chain [4] which contains an essential thiol in or near its active site [6, 7] and migrates to the a,-region on serum electrophoresis [8]. The highest specific activity is found in serum [9], suggesting that serum is the major site of action for the enzyme. It has also been suggested that biotinidase functions as a carrier of biotin in plasma [lO, ll]. In order to better understand the clinical heterogeneity observed in biotinidase deficiency, we have undertaken further characterization of the normal serum enzyme.
