Vanderpuye O A, Labarrere C A, McIntyre J A
Center for Reproduction and Transplantation Immunology, Methodist Hospital of Indiana, Indianapolis 46202.
Histochemistry. 1993 Sep;100(3):241-6. doi: 10.1007/BF00269097.
Prolyl 4-hydroxylase is a heterodimeric enzyme that is crucial in the biosynthesis of collagen. The beta subunit of this enzyme is a multifunctional protein which is also known as protein-disulfide isomerase. Immunofluorescence and monoclonal antibody (Mab) 5B5 were used to localize the beta subunit in human extraembryonic tissues. The strongest sites of 5B5 reactivity were extravillous cytotrophoblasts in the basal plate, uteroplacental arteries and amniochorion, syncytiotrophoblast displayed variable weaker reactivity. Only a small fraction of placental 5B5 antigen was detected as a component of prolyl-4-hydroxylase by affinity chromatography on immobilized polyproline. The results indicate a difference in the expression of an endoplasmic reticulum marker between villous and extravillous trophoblast. The predominance of 5B5 antigen in extravillous trophoblast could be associated with an increased ability to synthesize collagen or other enzymatic reactions associated with prolyl 4-hydroxylase beta subunit.
脯氨酰4-羟化酶是一种异源二聚体酶，在胶原蛋白的生物合成中起关键作用。该酶的β亚基是一种多功能蛋白，也被称为蛋白质二硫键异构酶。利用免疫荧光和单克隆抗体（Mab）5B5对人胚外组织中的β亚基进行定位。5B5反应最强的部位是基底板、子宫胎盘动脉和羊膜绒毛膜中的绒毛外细胞滋养层，合体滋养层的反应较弱且变化不定。通过固定化多聚脯氨酸亲和层析，仅检测到一小部分胎盘5B5抗原作为脯氨酰-4-羟化酶的一个组分。结果表明绒毛和绒毛外滋养层在内质网标志物表达上存在差异。绒毛外滋养层中5B5抗原的优势可能与合成胶原蛋白的能力增强或与脯氨酰4-羟化酶β亚基相关的其他酶促反应有关。
