Schenkels L C, Schaller J, Walgreen-Weterings E, Schadee-Eestermans I L, Veerman E C, Nieuw Amerongen A V
Department of Oral Biochemistry, Vrije Universiteit, Amsterdam, The Netherlands.
Biol Chem Hoppe Seyler. 1994 Sep;375(9):609-15. doi: 10.1515/bchm3.1994.375.9.609.
In this paper the identity of the salivary protein EP-GP (extra-parotid glycoprotein) is reported, also apparent in other human secretions. Immunochemical and biochemical analysis demonstrated that EP-GP is similar to the secretory actin-binding protein (SABP), also known as gross cystic disease fluid protein-15 (GCDFP-15) and prolactin-inducible protein (PIP). The molecular mass and charge microheterogeneity of EP-GP, also observed for SABP, was shown to be predominantly caused by the carbohydrate moiety. In addition, evidence was given that EP-GP is not related to the lipocalin Von Ebner's gland protein (human; VEGh). The biological significance of EP-GP and its homologues is not clear. EP-GP bound to actin and fibrinogen as described for SABP and GCDFP-15. However, the affinity for these proteins does not appear to have any direct physiological role in the mucosal secretions. On the other hand, EP-GP binds to several bacteria. By electron microscopy the ultrastructural localization is demonstrated of EP-GP to the cell wall of both Streptococcus salivarius HB and its cell appendage-lacking mutant Streptococcus salivarius HB-C12. Concerning this finding we hypothesize on the possible functional aspects of this enigmatic protein EP-GP.
本文报道了唾液蛋白EP-GP（腮腺外糖蛋白）的特性，该蛋白在其他人体分泌物中也很明显。免疫化学和生化分析表明，EP-GP与分泌型肌动蛋白结合蛋白（SABP）相似，后者也被称为大汗腺囊性病液蛋白-15（GCDFP-15）和催乳素诱导蛋白（PIP）。EP-GP的分子量和电荷微不均一性（SABP也有此现象）主要由碳水化合物部分引起。此外，有证据表明EP-GP与脂质运载蛋白埃伯纳腺蛋白（人；VEGh）无关。EP-GP及其同源物的生物学意义尚不清楚。EP-GP与肌动蛋白和纤维蛋白原结合，这与SABP和GCDFP-15的情况相同。然而，对这些蛋白质的亲和力在粘膜分泌物中似乎没有任何直接的生理作用。另一方面，EP-GP与几种细菌结合。通过电子显微镜证实了EP-GP在唾液链球菌HB及其缺乏细胞附属物的突变体唾液链球菌HB-C12细胞壁上的超微结构定位。关于这一发现，我们对这种神秘的蛋白质EP-GP可能的功能方面进行了推测。
