Adams E, Ramaswamy S, Lamon M
J Clin Invest. 1978 Jun;61(6):1482-7. doi: 10.1172/JCI109068.
Values for total 3-hydroxyproline and 4-hydroxyproline were obtained from 24-h urine specimens of 18 healthy human subjects of both sexes, whose ages ranged from the first to the sixth decade in age. Urinary 3-hydroxyproline levels, not earlier described to our knowledge, were determined by an isotope-dilution method requiring considerable purification and utilizing the amino acid analyzer for final measurement. 3-Hydroxyproline averaged 3% of the corresponding 4-hydroxyproline in individual urine samples. Like 4-hydroxyproline, 3-hydroxyproline excretion is increased in the second decade, and there is generally good correlation between the two values in individual urines. A hydroxyprolinemic subject excreting greatly elevated 4-hydroxyproline levels did not excrete excessive 3-hydroxyproline, consistent with independent catabolic pathways for the two compounds. 3-Hydroxyproline appears to be selectively excreted relative to 4-hydroxyproline when compared with the probable total body content of each amino acid. Possible explanations are: a more rapid turnover of basement membrane collagen than interstitial collagen or, alternatively, relatively greater resistance to the proteolytic cleavage of peptides containing 3-hydroxyproline.
从18名年龄跨度从20岁到60岁的健康男女受试者的24小时尿液样本中获取了总3-羟基脯氨酸和4-羟基脯氨酸的值。据我们所知，尿中3-羟基脯氨酸水平此前未见报道，采用一种需要大量纯化且利用氨基酸分析仪进行最终测量的同位素稀释法进行测定。在个体尿液样本中，3-羟基脯氨酸平均占相应4-羟基脯氨酸的3%。与4-羟基脯氨酸一样，3-羟基脯氨酸的排泄量在第三个十年有所增加，且个体尿液中这两个值通常具有良好的相关性。一名4-羟基脯氨酸排泄量大幅升高的高羟脯氨酸血症受试者并未排泄过量的3-羟基脯氨酸，这与这两种化合物的独立分解代谢途径一致。与每种氨基酸的可能全身含量相比，3-羟基脯氨酸似乎相对于4-羟基脯氨酸被选择性排泄。可能的解释是：基底膜胶原蛋白的周转速度比间质胶原蛋白更快，或者，含3-羟基脯氨酸的肽对蛋白水解切割的抵抗力相对更强。
