血清淀粉样蛋白（9.5Sα1-糖蛋白）的结构与结合特性。

The structure and binding characteristics of serum amyloid protein (9.5S alpha 1-glycoprotein).

作者信息

Painter R H, De Escallón I, Massey A, Pinteric L, Stern S B

出版信息

Ann N Y Acad Sci. 1982;389:199-215. doi: 10.1111/j.1749-6632.1982.tb22138.x.

DOI:10.1111/j.1749-6632.1982.tb22138.x

Abstract

No difference have been observed in the properties of amyloid P-component (AP) and its serum counterpart (SAP) which might account for the deposition of the former in amyloidosis. Purified by nonselective techniques, preparations of AP and SAP were shown to have similar molecular weights and peptide composition, identical morphology in the electron microscope (EM) and to be antigenically indistinguishable. Both proteins were soluble in EDTA but readily precipitated in the presence of calcium ions, forming characteristic two-dimensional arrays in the EM. In serum however, SAP was not aggregated and sedimented at 9.5S in Ca2+ as did the purified protein in EDTA. Precipitation of purified SAP by calcium could be prevented by pretreatment with acid hydrolysates of agarose or SP Sephadex, matrices for which SAP has a calcium-dependent affinity. It is proposed that SAP circulates in combination with a low molecular weight natural ligand which prevents its aggregation. While the identity of natural ligand for SAP is as yet unknown, it is likely to resemble the glycosidic subunits in agarose.

摘要

在淀粉样蛋白P成分（AP）及其血清对应物（SAP）的特性方面未观察到差异，而这种差异可能解释了前者在淀粉样变性中的沉积。通过非选择性技术纯化后，AP和SAP制剂显示出相似的分子量和肽组成，在电子显微镜（EM）下具有相同的形态，并且在抗原性上无法区分。两种蛋白质都可溶于EDTA，但在钙离子存在下很容易沉淀，在EM中形成特征性的二维阵列。然而，在血清中，SAP不像在EDTA中的纯化蛋白那样在Ca2+中聚集并沉淀在9.5S处。用琼脂糖或SP Sephadex的酸水解产物预处理可以防止纯化的SAP被钙沉淀，SAP对这些基质具有钙依赖性亲和力。有人提出，SAP与一种低分子量天然配体结合循环，这种配体可防止其聚集。虽然SAP天然配体的身份尚不清楚，但它可能类似于琼脂糖中的糖苷亚基。