Brown M A, Carne A, Chambers G K
Biochemistry and Genetics Research Unit, School of Biological Sciences, Victoria University of Wellington, New Zealand.
Comp Biochem Physiol B Biochem Mol Biol. 1996 Apr;113(4):731-6. doi: 10.1016/0305-0491(95)02088-8.
alpha 2-Macroglobulin (alpha 2-M), a large molecular mass proteinase-binding protein, was identified in plasma from tuatara (Sphenodon), a rare reptile endemic to New Zealand. In this genus, alpha 2-M constitutes 11-13% of total plasma protein (approximately 2.2-3.9 mg/mL). Analysis of blood samples collected at approximately monthly intervals from individual tuatara indicated that the plasma level of alpha 2-M remains fairly constant. The subunits of tuatara alpha 2-M have an apparent molecular mass of approximately 160 kDa as determined by SDS-polyacrylamide gel electrophoresis and the intact protein is an oligomer that contains inter-chain disulfide bonds. N-terminal sequence analyses of tuatara alpha 2-M revealed a distinct similarity to alpha-macroglobulins of other vertebrates and that at least two types of alpha 2-M subunits are present in plasma of tuatara.
α2-巨球蛋白（α2-M）是一种大分子质量的蛋白酶结合蛋白，在来自新西兰特有的珍稀爬行动物楔齿蜥的血浆中被鉴定出来。在该属动物中，α2-M占血浆总蛋白的11%-13%（约2.2-3.9毫克/毫升）。对从单个楔齿蜥大约每月采集一次的血样分析表明，α2-M的血浆水平保持相当稳定。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳测定，楔齿蜥α2-M的亚基表观分子量约为160千道尔顿，完整的蛋白质是一种含有链间二硫键的寡聚体。楔齿蜥α2-M的N端序列分析显示，它与其他脊椎动物的α-巨球蛋白有明显的相似性，并且楔齿蜥血浆中至少存在两种类型的α2-M亚基。
