Bogusiewicz Anna, Stratton Shawna L, Ellison Dale A, Mock Donald M
Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Am J Clin Nutr. 2008 Nov;88(5):1291-6. doi: 10.3945/ajcn.2008.26525.
Biotin is likely transported into cerebral spinal fluid (CSF) via one or more specific transporters. Concentrations of biotin in CSF measured by using modern analytic techniques that are specific for biotin and biotin metabolites have not previously been reported.
We aimed to accurately measure the concentration of biotin and major biotin metabolites, biotin sulfoxide (BSO) and bisnorbiotin (BNB), in the CSF of children.
Concentrations of biotin were determined initially as total avidin-binding substances (TABS) in CSF obtained by lumbar puncture from 55 children. Biotin, BSO, and BNB were quantitated by HPLC and an avidin-binding assay in CSF samples from a subset of 11 children.
Concentrations of TABS in CSF averaged 1.6 nmol/L with substantial variability (SD = 1.3 nmol/L). CSF concentrations of biotin and biotin analogs varied widely, but substantial amounts of BSO were detected in every sample. Biotin accounted for 42 +/- 16%, BSO for 41 +/- 12%, and BNB for 8 +/- 14% of the total. It was surprising that the molar sum of biotin, BSO, and BNB on average was >200-fold the TABS concentrations from the same CSF sample. Using several analytic approaches, we found no masking of detection, nor did we find degradation of biotin or BSO. Gel electrophoresis and streptavidin Western blot detected several biotinylated proteins in CSF.
Biotin appears to be bound to protein covalently, reversibly, or both, and this binding likely accounts for the increase in detectable biotin after HPLC. Protein-bound biotin may play an important role in biotin nutriture of the brain.
生物素可能通过一种或多种特定转运蛋白进入脑脊液（CSF）。此前尚未有使用针对生物素和生物素代谢物的现代分析技术测量脑脊液中生物素浓度的报道。
我们旨在准确测量儿童脑脊液中生物素及主要生物素代谢物——生物素亚砜（BSO）和双去甲生物素（BNB）的浓度。
最初通过腰椎穿刺从55名儿童获取脑脊液，将其中生物素浓度测定为总抗生物素蛋白结合物质（TABS）。对11名儿童子集的脑脊液样本，通过高效液相色谱法（HPLC）和抗生物素蛋白结合测定法定量生物素、BSO和BNB。
脑脊液中TABS浓度平均为1.6 nmol/L，差异较大（标准差 = 1.3 nmol/L）。脑脊液中生物素和生物素类似物的浓度差异很大，但每个样本中均检测到大量的BSO。生物素占总量的42±16%，BSO占41±12%，BNB占8±14%。令人惊讶的是，同一脑脊液样本中生物素、BSO和BNB的摩尔总和平均比TABS浓度高200倍以上。使用多种分析方法，我们未发现检测被掩盖的情况，也未发现生物素或BSO降解。凝胶电泳和链霉抗生物素蛋白免疫印迹法在脑脊液中检测到几种生物素化蛋白。
生物素似乎与蛋白质发生共价结合、可逆结合或两者兼有，这种结合可能是HPLC后可检测到的生物素增加的原因。蛋白质结合型生物素可能在大脑的生物素营养中起重要作用。
