Biotinidase deficiency in juvenile multiple carboxylase deficiency.
Biotinidase deficiency in juvenile multiple carboxylase deficiency.
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幼年多种羧化酶缺乏症中的生物素酶缺乏症。
DOI：
10.1016/s0140-6736(83)90364-1
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Wolf,B
中科院分区：
文献类型：
--
作者：
Thoene,J;Wolf,B
然而，在摄入5J·lg/kg生物素后1小时，她的血浆生物素浓度上升到5650pg/ml，与类似处理的充满生物素的对照组一样。生物素清除也正常(34~4.4ml/min/1.73m2)。服用生物素后24小时尿中生物素排泄量为50‘8%，是对照组的两倍，是之前最大排泄量(15%)的三倍多。患者血清中的生物素酶活性检测不到(表)。这位母亲没有临床上的生物素缺乏症，生物素酶平均活性为46%，血浆生物素为248 pg/ml，低于正常水平。膳食生物素主要以生物素基团的形式存在，与蛋白质赖氨酸残基的E-氨基相连。生物素酶能分解这个键，释放出游离的生物素。生物素酶活性广泛分布，特别是在肝、肾、血清和肠粘膜中。9虽然这种酶对饮食蛋白质的主要作用部位尚不清楚，但缺乏可能会削弱维持体内正常储存的游离生物素的能力，导致低生物素血症。生物素酶是否也参与了游离生物素的吸收尚不清楚。当患者的组织充满生物素时，患者对摄入5pg/kg生物素的正常血浆生物素反应，但当她缺乏生物素时，她的反应失败可能是由于生物素迅速进入耗尽的组织。相似的结果
However, 1 h after ingestion of 5 J. lg/kg of biotin, her plasma biotin concentration rose to 5650 pg/ml, as in similarly treated biotin-replete controls. Biotin clearance was also normal (34-4 4 ml/min/1’73 m2). The fraction of biotin excreted in her urine in the 24 h after the biotin dose was 50’8%, twice as high as the amount excreted by the controls and more than three times her previous maximum excretion (15%). Biotinidase activity in the patient’s serum was undetectable (table). The mother, who does not have clinical biotin deficiency, had 46% of mean normal biotinidase activity and a plasma biotin of 248 pg/ml, which is below normal. Dietary biotin exists primarily as biotinyl groups linked to the E-amino groups of lysine residues of proteins. 9 Biotinidase hydrolyses this bond, releasing free biotin. Biotinidase activity is widely distributed, particularly in liver, kidney, serum, and gut mucosa. 9 Although this enzyme’s primary site of action on dietary protein is not known, deficiency could impair ability to maintain normal body stores of free biotin, leading to a hypobiotinaemic state. Whether biotinidase is also involved in the absorption of free biotin is not known.The patient’s normal plasma biotin response to the ingestion of 5pg/kg of biotin when her tissues were replete with biotin, but her failure to respond when she was biotin deficient is probably caused by rapid entry of biotin into the depleted tissues. Similar results