Smith A J, Leaver A G, Smith G
Arch Oral Biol. 1983;28(11):1047-54. doi: 10.1016/0003-9969(83)90061-4.
Human cementum was demineralized and exhaustively extracted with EDTA and then digested with collagenase. The insoluble residue after digestion was extracted successively with 8M urea and with 8M urea containing 0.1M mercaptoethanol. The non-collagenous fraction accounted for a larger proportion of the total organic matrix than previously found in bone and dentine, largely due to the presence of more collagenase-insoluble material. Fractionation of the EDTA-soluble material resulted in less-acidic fractions, showing similarities to the corresponding fractions of bone and dentine, and anionic fractions with lower levels of acidic amino acids than those from other hard tissues. Fractions obtained from the soluble collagenase-released material after ion-exchange chromatography and gel filtration, although more heterogeneous than those of bone and dentine, showed many similarities, thus confirming the close homology within this fraction from the various hard tissues. The insoluble residue after collagenase digestion appeared to be of the acid-structural protein type found also in bone, dentine and a wide range of connective tissues.
人牙骨质经脱矿处理后，先用乙二胺四乙酸（EDTA）彻底提取，然后用胶原酶消化。消化后的不溶性残渣先后用8M尿素和含0.1M巯基乙醇的8M尿素提取。非胶原蛋白部分在总有机基质中所占比例比先前在骨和牙本质中发现的更大，这主要是由于存在更多的胶原酶不溶性物质。对EDTA可溶性物质进行分级分离得到酸性较低的部分，与骨和牙本质的相应部分相似，以及酸性氨基酸水平低于其他硬组织的阴离子部分。离子交换色谱和凝胶过滤后从可溶性胶原酶释放物质中获得的部分，虽然比骨和牙本质的部分更具异质性，但显示出许多相似之处，从而证实了来自各种硬组织的该部分之间的密切同源性。胶原酶消化后的不溶性残渣似乎是在骨、牙本质和多种结缔组织中也发现的酸性结构蛋白类型。
