Ali S Y, Sajdera S W, Anderson H C
Proc Natl Acad Sci U S A. 1970 Nov;67(3):1513-20. doi: 10.1073/pnas.67.3.1513.
Matrix vesicles, associated with initial calcification in cartilage, have been isolated from bovine fetal epiphyseal cartilage. Cartilage was digested with collagenase, then partitioned into seven fractions by differential centrifugation. The cellular fractions contained over 80% of the DNA in the digest. The extracellular fraction that contained matrix vesicles, in which apatite crystals were often seen on electron microscopy, also displayed the highest specific activity for alkaline phosphatase, pyrophosphatase, ATPase, and 5'-AMPase (EC 3.1.3.1., 3.6.1.1, 3.6.1.3, and 3.1.3.5, respectively). Most of the acid phosphatase (EC 3.1.3.2) activity, on the other hand, was found in the cellular fractions, indicating that matrix vesicles are quite distinct from lysosomes. This appears to be the first instance of isolation of membrane-bounded extracellular particles from any normal tissue. The matrix vesicles possess enzymes that can increase the local concentration of orthophosphate and thus could lead to the formation of hydroxyapatite. The membrane-bounded matrix vesicles may also provide a mechanism for ATP-dependent transport of calcium or phosphate into the lumen of the vesicles with resultant mineralization.
已从牛胎儿骺软骨中分离出与软骨初始钙化相关的基质小泡。用胶原酶消化软骨，然后通过差速离心将其分成七个部分。细胞部分含有消化物中80%以上的DNA。含有基质小泡的细胞外部分，在电子显微镜下经常可见磷灰石晶体，其碱性磷酸酶、焦磷酸酶、ATP酶和5'-AMP酶（分别为EC 3.1.3.1、3.6.1.1、3.6.1.3和3.1.3.5）的比活性也最高。另一方面，大部分酸性磷酸酶（EC 3.1.3.2）活性存在于细胞部分，这表明基质小泡与溶酶体截然不同。这似乎是首次从任何正常组织中分离出有膜包被的细胞外颗粒。基质小泡拥有能增加局部正磷酸盐浓度的酶，因此可能导致羟基磷灰石的形成。有膜包被的基质小泡还可能为ATP依赖的钙或磷酸盐转运到小泡腔内并最终矿化提供一种机制。
