Rathman W M, van Zeyl M J, van den Keijbus P A, Veerman E C, Nieuw Amerongen A V
Department of Oral Biochemistry, Academic Centre for Dentistry Amsterdam (ACTA).
J Biol Buccale. 1990 Mar;18(1):9-18.
An acidic protein with a molecular weight of 14 kD and a cysteine proteinase inhibitory activity was isolated from human whole salive. It was classified therefore as a cystatin. Fractionation of whole saliva by FPLC ion-exchange chromatography, followed by immunochemical analysis with monoclonal antibodies, indicated that this protein, designated 14 kD/E8B, eluted in a single peak, which comprised 6% of the total salivary cystatin-activity. The 14 kD/E8B cystatin had nearby 5 times less apparent affinity for papain than chicken egg cystatin. In addition to 14 kD/E8B cystatin, four other cystatins were separated, having pI values of 4.5 and 4.7. One of these appeared together with amylase. Furthermore a protein having a pI of 6.7 was isolated, which accounted for approximately 50% of the total cystatin activity present in whole saliva. The total cystatin activity in unstimulated whole saliva showed at least a three fold difference between individuals. Specific cystatin activity, based on protein content, was highest in saliva derived from the submandibular gland. In addition, cystatin activity could be detected in sublingual and labial saliva, whereas parotid saliva displayed little activity and palatinal saliva no activity at all.
从人全唾液中分离出一种分子量为14 kD且具有半胱氨酸蛋白酶抑制活性的酸性蛋白。因此，它被归类为一种半胱氨酸蛋白酶抑制剂。通过快速蛋白质液相色谱离子交换色谱法对全唾液进行分级分离，随后用单克隆抗体进行免疫化学分析，结果表明这种名为14 kD/E8B的蛋白以单峰形式洗脱，占唾液中半胱氨酸蛋白酶抑制剂总活性的6%。14 kD/E8B半胱氨酸蛋白酶抑制剂对木瓜蛋白酶的表观亲和力比鸡卵半胱氨酸蛋白酶抑制剂低近5倍。除了14 kD/E8B半胱氨酸蛋白酶抑制剂外，还分离出了其他四种半胱氨酸蛋白酶抑制剂，其pI值分别为4.5和4.7。其中一种与淀粉酶一起出现。此外，还分离出了一种pI为6.7的蛋白，它约占全唾液中半胱氨酸蛋白酶抑制剂总活性的50%。未刺激的全唾液中的半胱氨酸蛋白酶抑制剂总活性在个体之间至少相差三倍。基于蛋白质含量的比半胱氨酸蛋白酶抑制剂活性在来自下颌下腺的唾液中最高。此外，在舌下和唇腺唾液中可检测到半胱氨酸蛋白酶抑制剂活性，而腮腺唾液中活性较低，腭腺唾液中则完全没有活性。
