Morioka Y, Kobayashi K
Diagnostic Science Division, Shionogi & Co., Ltd., Settsu, Japan.
Biol Pharm Bull. 1997 Aug;20(8):825-7. doi: 10.1248/bpb.20.825.
We developed a simple method for the quantification of cystine (disulfide bond) content in hair by measuring the amount of oxidized dithiothreitol (lambda max 283 nm) derived from dithiothreitol (DTT) with cystine. Because the cystine content in hair is almost fixed for each animal species, it can be used as a reliable indicator of hair weight. The absorbance (A280, y) of the supernatant of the reaction mixture correlated well with hair weight (mg, x) (y = 0.10x + 0.06, r = 1.00, n = 10). Within-run and between-day reproducibilities (C.Vs., %) for the assay were 3.1 and 2.8 (n = 5 each), respectively. Hair cystine content (nmol/mg hair, mean +/- S.D.) in normal volunteers was 903 +/- 50.6 (n = 10) by the present method and 755 +/- 24.9 (n = 10) when an amino acid analyzer was used. After assay by our method, the hair sample can be washed, then used repeatedly to assay other analytes. The present method should be useful for assays of analytes present only in small amounts (2-20 mg), without the need for precise weighing of the hair samples.
我们开发了一种简单的方法来定量测定毛发中的胱氨酸（二硫键）含量，即通过测量由二硫苏糖醇（DTT）与胱氨酸反应生成的氧化型二硫苏糖醇（最大吸收波长283nm）的量来实现。由于每种动物毛发中的胱氨酸含量几乎是固定的，因此它可作为毛发重量的可靠指标。反应混合物上清液的吸光度（A280，y）与毛发重量（mg，x）具有良好的相关性（y = 0.10x + 0.06，r = 1.00，n = 10）。该测定方法的批内和批间重复性（变异系数，%）分别为3.1和2.8（每组n = 5）。采用本方法时，正常志愿者毛发中的胱氨酸含量（nmol/mg毛发，平均值±标准差）为903±50.6（n = 10），而使用氨基酸分析仪时为755±24.9（n = 10）。用我们的方法测定后，毛发样品可以洗涤，然后重复用于测定其他分析物。本方法对于仅存在少量（2 - 20mg）分析物的检测应该是有用的，无需精确称量毛发样品。
