Huszar G, Bailey P
Am J Obstet Gynecol. 1979 Nov 15;135(6):707-12. doi: 10.1016/0002-9378(79)90379-x.
The major contractile protein myosin was isolated and characterized from the smooth muscle of human term placentas. Placental myosin originates chiefly in the anchoring villi which bridge the fetal and maternal surfaces of the placenta. The molecular weight of placental myosin is about 460,000; it is composed of two heavy chains of 200,000 molecular weight and two pairs of light chains with 13,500 and 17,500 molecular weights. The adenosine triphosphatase (ATPase) of the myosin is activated by potassium and calcium and it is inhibited by magnesium. Placental actomyosin ATPase is activated by magensium. Contraction and relaxation of the smooth muscle in the anchoring villi are thought to adjust the volume of the intervillous space; thus, actin-myosin interaction is implicated in the regulation of placental hemodynamics.
主要收缩蛋白肌球蛋白是从足月人胎盘的平滑肌中分离并鉴定出来的。胎盘肌球蛋白主要起源于连接胎盘胎儿面和母体面的固定绒毛。胎盘肌球蛋白的分子量约为460,000；它由两条分子量为200,000的重链和两对分子量分别为13,500和17,500的轻链组成。肌球蛋白的三磷酸腺苷酶（ATP酶）被钾和钙激活，被镁抑制。胎盘肌动球蛋白ATP酶被镁激活。固定绒毛中平滑肌的收缩和舒张被认为可调节绒毛间隙的容积；因此，肌动蛋白-肌球蛋白相互作用与胎盘血液动力学的调节有关。
