Hay D I, Smith D J, Schluckebier S K, Moreno E C
J Dent Res. 1984 Jun;63(6):857-63. doi: 10.1177/00220345840630060901.
Human salivary secretions are supersaturated with respect to the calcium phosphate salts which form dental enamel, a property which provides important protection for the teeth. We previously proposed that statherin, a 43-residue phosphopeptide, plays a key role in this protective system by inhibiting or delaying potentially harmful precipitation of calcium phosphate salts in the salivary glands and mouth. The purpose of the present study was to determine if the concentrations of statherin in saliva, despite their wide normal range, are high enough to fulfill this function. Concentrations of statherin in stimulated human parotid saliva samples from 36 female and 32 male subjects, aged from 17 to 30 years, were determined by a single radial immunodiffusion method. Values found ranged from 3.0 to greater than 27.3 microM, with a mean value of 12.8 (S.D. +/- 5.46) microM. At concentrations below these values, statherin inhibited spontaneous precipitation of calcium phosphate salts from an assay system which was more supersaturated with respect to dicalcium phosphate dihydrate, and comparably supersaturated with respect to hydroxyapatite, than were human saliva samples. The inhibitory activities of five of the 65 stimulated parotid saliva samples assayed were greater than would be anticipated from their statherin concentrations. This unexplained discrepancy is not associated with the presence of the acidic proline-rich proteins in saliva, although these proteins also affect calcium phosphate precipitation. The results of this study show that statherin is present in stimulated human parotid saliva at concentrations and levels of activity which are consistent with its proposed biological function, and support the proposal that statherin plays a significant role in a system which provides a protective and reparative but stable environment for the teeth.
人类唾液分泌物对于形成牙釉质的磷酸钙盐而言是过饱和的，这一特性为牙齿提供了重要保护。我们之前提出，一种由43个氨基酸残基组成的磷肽——组蛋白，通过抑制或延缓唾液腺和口腔中磷酸钙盐潜在的有害沉淀，在这个保护系统中发挥关键作用。本研究的目的是确定，尽管唾液中组蛋白的浓度在正常范围内波动很大，但这些浓度是否足以发挥这一功能。通过单向辐射免疫扩散法测定了36名17至30岁女性和32名男性受试者的刺激性腮腺唾液样本中组蛋白的浓度。测得的值在3.0至大于27.3微摩尔/升之间，平均值为12.8（标准差±5.46）微摩尔/升。在低于这些值的浓度下，组蛋白抑制了来自一个比人类唾液样本对二水磷酸二钙过饱和度更高、对羟基磷灰石过饱和度相当的分析系统中磷酸钙盐的自发沉淀。在检测的65个刺激性腮腺唾液样本中，有5个样本的抑制活性高于根据其组蛋白浓度预期的值。这种无法解释的差异与唾液中富含酸性脯氨酸的蛋白质的存在无关，尽管这些蛋白质也会影响磷酸钙沉淀。本研究结果表明，组蛋白以与其假定的生物学功能一致的浓度和活性水平存在于刺激性人类腮腺唾液中，并支持组蛋白在为牙齿提供保护、修复但稳定环境的系统中发挥重要作用的提议。
