Tyrosine uptake in normal and albino hairbulbs.
Tyrosine uptake in normal and albino hairbulbs.
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正常和白化毛球中酪氨酸的吸收。
DOI：
10.1007/bf00404623
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发表时间：
1984
影响因子：
3
通讯作者：
Olds,DP
中科院分区：
文献类型：
--
作者：
King,RA;Olds,DP
开发了一种用于测量人毛球的酪氨酸摄取的方法，以进一步表征人体组织中黑色素形成的过程。通过在含有放线菌酮和过氧化氢酶的HEPES-Tris缓冲液中的14 C-酪氨酸中孵育新鲜生长期毛球来测定摄取。11名棕色、黑色、金色和红色头发的正常色素受试者的吸收范围为295 cpm/24 h（金色受试者的毛球）至6661 cpm/24 h（红色头发受试者的毛球）。来自IIA型（酪氨酸酶阳性）眼皮肤白化病患者的毛球，每个毛球的吸收率为2995 cpm/24 h。白色毛球的吸收为265 cpm/24 h/毛球。有一个很好的相关性（r=0.86）之间的摄取水平和酪氨酸酶（酪氨酸羟化酶）活性的水平，当这些值进行比较，为10名受试者。酪氨酸酶活性的抑制，摄取减少。低孵育温度（4° C和21°C）和向孵育液中添加未标记酪氨酸也会降低摄取。14%~ 19%的14 C-酪氨酸被提取为14 C-黑色素。这些结果表明，通过该实验方法测定的酪氨酸的摄取依赖于黑素细胞和酪氨酸酶的存在，与酪氨酸酶活性水平定量相关，并且似乎是代谢过程。IIA型白化病毛球黑素细胞似乎能够运输足够量的底物。
A method for measuring tyrosine uptake by human hairbulbs was developed to further characterize the process of melanin formation in human tissue. Uptake was determined by incubating fresh anagen hairbulbs in14C-tyrosine in HEPES-Tris buffer containing cycloheximide and catalase. Uptake for 11 normally pigmented subjects with brown, black, blond and red hair ranged from 295 cpm/24h per hairbulb for hairbulbs from a blond subject to 6661 cpm/24h per hairbuld for hairbulbs from a red-haired subject. Hairbulbs from a type IIA (tyrosinase-positive) oculocutaneous albino and an uptake of 2995 cpm/24 h per hairbulb. White hairbulbs had an uptake of 265 cpm/ 24h per hairbulb. There was a good correlation (r=0.86) between the level of uptake and the level of tyrosinase (tyrosine hydroxylase) activity when these values were compared for ten subjects. Uptake was reduced with the inhibition of tyrosinase activity. Uptake was also reduced with low incubation temperatures (4° and 21°C) and with the addition of unlabeled tyrosine to the incubation. From 14% to 19% of the14C-tyrosine that was taken up could be extracted as14C-melanin. These results show that the uptake of tyrosine as determined by this experimental method is dependent on the presence of melanocytes and tyrosinase, is quantitatively related to the level of tyrosinase activity, and appears to be a metabolic process. Type IIA albino hairbulb melanocytes appear able, to transport adequate amounts of substrate.