Chesson Lesley A, Podlesak David W, Cerling Thure E, Ehleringer James R
Biology Department, University of Utah, Salt Lake City, UT 84112, USA.
Rapid Commun Mass Spectrom. 2009 May;23(9):1275-80. doi: 10.1002/rcm.4000.
We calculated the fraction of exchangeable hydrogen atoms in proteinaceous materials commonly analyzed for stable isotopic composition related to the region-of-origin of an animal. These included several types of alpha- and beta-keratin, and muscle tissue. We find that the fraction of H atoms in keratin available for exchange at a biologically relevant temperature (25 degrees C) averaged 9% across a range of ground organic materials, but was as high as approximately 17% in cut hair; muscle tissue has approximately 12% exchangeable H atoms. Under most analysis conditions, the difference in exchangeable fractions due to physical sample processing has a minimal effect on the calculated delta2H values of the non-exchangeable H atoms within a keratin-containing tissue (<2 per thousand). However, extreme mismatches between sample and reference material types could affect delta2H values.
我们计算了通常用于分析与动物原产地相关稳定同位素组成的蛋白质材料中可交换氢原子的比例。这些材料包括几种α-和β-角蛋白以及肌肉组织。我们发现，在一系列磨碎的有机材料中，角蛋白中在生物学相关温度（25摄氏度）下可用于交换的氢原子比例平均为9%，但在剪下的毛发中高达约17%；肌肉组织有大约12%的可交换氢原子。在大多数分析条件下，由于物理样品处理导致的可交换比例差异对含角蛋白组织中不可交换氢原子的计算δ2H值影响极小（<2‰）。然而，样品和参考材料类型之间的极端不匹配可能会影响δ2H值。
