Noguchi C T, Luskey K L, Pavone V
Mol Pharmacol. 1985 Jul;28(1):40-4.
To examine in detail a class of peptides that inhibit the polymerization of deoxyhemoglobin S, we assayed the L-amino acids and 22 dipeptides for their effect on deoxyhemoglobin S solubility. Of the amino acids, the aromatics (phenylalanine, tyrosine, and tryptophan) significantly increased deoxyhemoglobin S solubility, as did high concentration of arginine. Combinations of the hydrophobic (specifically the aromatic) amino acids with a hydrophilic amino acid, such as arginine or lysine, resulted in dipeptides which were much more soluble than the hydrophobic or aromatic amino acid alone, and also inhibited polymerization. Furthermore, samples of deoxyhemoglobin S at 26 to 27 g/dl containing some of these dipeptides such as Arg-Trp, Arg-Phe, and Lys-Trp in excess of 50 to 100 mM did not polymerize, indicating a 1.4- to 1.6-fold increase in deoxyhemoglobin S solubility. The enhancement of polymerization, i.e., decrease in deoxyhemoglobin S solubility, observed by the addition of aspartic acid, glycine, or lysine was observed or was reduced in the dipeptides containing these hydrophilic amino acids combined with hydrophobic amino acids (valine, leucine, isoleucine, or the aromatic amino acids). The effects of these dipeptides on deoxyhemoglobin S solubility were mostly linear with concentration. However, the changes in deoxyhemoglobin S solubility by addition of a dipeptide was not simply the sum of the effects observed with the individual amino acids as exemplified by the differential effect of reversing the dipeptide sequence (e.g., Arg-Phe and Phe-Arg, or Arg-Tyr and Tyr-Arg). These data provide further evidence as to the stereospecific nature of this class of noncovalent inhibitors of deoxyhemoglobin S polymerization.
为了详细研究一类抑制脱氧血红蛋白S聚合的肽，我们检测了L-氨基酸和22种二肽对脱氧血红蛋白S溶解度的影响。在这些氨基酸中，芳香族氨基酸（苯丙氨酸、酪氨酸和色氨酸）以及高浓度的精氨酸显著提高了脱氧血红蛋白S的溶解度。疏水性（特别是芳香族）氨基酸与亲水性氨基酸（如精氨酸或赖氨酸）的组合产生的二肽，其溶解度比单独的疏水性或芳香族氨基酸高得多，并且还能抑制聚合。此外，在26至27 g/dl的脱氧血红蛋白S样品中，含有超过50至100 mM的一些此类二肽（如Arg-Trp、Arg-Phe和Lys-Trp）不会发生聚合，这表明脱氧血红蛋白S的溶解度增加了1.4至1.6倍。通过添加天冬氨酸、甘氨酸或赖氨酸观察到的聚合增强，即脱氧血红蛋白S溶解度降低，在含有这些亲水性氨基酸与疏水性氨基酸（缬氨酸、亮氨酸、异亮氨酸或芳香族氨基酸）组合的二肽中也观察到或有所降低。这些二肽对脱氧血红蛋白S溶解度的影响大多与浓度呈线性关系。然而，添加二肽引起的脱氧血红蛋白S溶解度变化并非简单地是单个氨基酸效应的总和，例如二肽序列颠倒时的差异效应（如Arg-Phe和Phe-Arg，或Arg-Tyr和Tyr-Arg）就说明了这一点。这些数据进一步证明了这类脱氧血红蛋白S聚合的非共价抑制剂的立体特异性性质。
