Kawai T, Urist M R
UCLA Bone Research Laboratory, 90024-1790.
J Dent Res. 1989 Jun;68(6):1069-74. doi: 10.1177/00220345890680060301.
Eight groups of dental tissues were mechanically dissected from the mandibles of one-year-old steers; they were then defatted and decalcified in HCl. The noncollagenous proteins were extracted with various solvents from collections of tissue and bio-assayed for osteo-inductive activity. Collectively, the hard tissue (dentin, enamel, and cementum) noncollagenous proteins were fractionated by molecular sieve chromatography, hydroxyapatite affinity chromatography, and ion exchange chromatography. Osteo-inductive activity of each protein fraction was determined by implantation in the quadriceps muscle pouch of mice. The quantity of bone was measured by computerized image analysis. From 71% to 83% of 41 implants of dental hard tissues induced bone formation. The quantity of bone was greater from unerupted than from erupted teeth. Dental soft tissues that had no osteo-inductive activity were rich in a 14-kDa protein, presumably matrix gamma-carboxyglutamic acid-rich proteins. Proteins with Mr of from 15 to 28 kDa were associated with osteo-inductive activity. Components with Mr greater than 28 kDa had no activity. These observations suggest that bovine teeth have a selection of osteo-inductive proteins that is comparable in range of MW to bovine bone morphogenetic protein.
从一岁公牛的下颌骨中机械分离出八组牙齿组织；然后将它们脱脂并在盐酸中脱钙。用各种溶剂从组织样本中提取非胶原蛋白，并对其骨诱导活性进行生物测定。总体而言，通过分子筛色谱、羟基磷灰石亲和色谱和离子交换色谱对硬组织（牙本质、牙釉质和牙骨质）非胶原蛋白进行分级分离。通过植入小鼠股四头肌袋来测定每个蛋白质级分的骨诱导活性。通过计算机图像分析测量骨量。41个牙齿硬组织植入物中有71%至83%诱导了骨形成。未萌出牙齿诱导形成的骨量比已萌出牙齿的多。没有骨诱导活性的牙齿软组织富含一种14 kDa的蛋白质，可能是富含γ-羧基谷氨酸的基质蛋白。分子量在15至28 kDa之间的蛋白质与骨诱导活性相关。分子量大于28 kDa的组分没有活性。这些观察结果表明，牛牙齿具有一系列骨诱导蛋白，其分子量范围与牛骨形态发生蛋白相当。
