Moradian-Oldak J, Gharakhanian N, Jimenez I
Center for Craniofacial Molecular Biology, University of Southern California School of Dentistry, 2250 Alcazar St., CSA 1st Floor, Los Angeles, CA 90033, USA.
Connect Tissue Res. 2002;43(2-3):450-5. doi: 10.1080/03008200290000835.
This article is a short review of our recent study on controlled proteolysis of amelogenins by a series of commercially available proteinases as well as the tooth-specific metalloproteinase enamelysin. A limited proteolysis approach and mass spectrometry were applied in order to determine the surface accessibility of conserved domains of amelogenin nanospheres. Furthermore, this study was aimed at exploring the factors that affect the activity of enamel proteases to process amelogenins and at providing insight into the mechanisms of amelogenin degradation during amelogenesis. We found that, under limited conditions, certain amino acid residues at both the C- and N-termini of amelogenin are accessible to proteolytic action by a series of proteinases, suggesting that these regions are exposed on the surface of amelogenin nanospheres. Recombinant enamelysin cleaved amelogenin at the C-terminal region, showing a preference of the enzyme to cleave the S/M and F/S bonds. This result of enamelysin activity on amelogenin explains the abundance of the p148 (20k) pig amelogenin during the secretory stage of amelogenesis.
本文是对我们近期研究的简要回顾，该研究涉及一系列市售蛋白酶以及牙齿特异性金属蛋白酶釉质溶解素对釉原蛋白的可控蛋白水解作用。采用有限蛋白水解方法和质谱分析法来确定釉原蛋白纳米球保守结构域的表面可及性。此外，本研究旨在探索影响釉质蛋白酶处理釉原蛋白活性的因素，并深入了解釉质形成过程中釉原蛋白降解的机制。我们发现，在有限条件下，一系列蛋白酶可对釉原蛋白C末端和N末端的某些氨基酸残基进行蛋白水解作用，这表明这些区域暴露于釉原蛋白纳米球表面。重组釉质溶解素在C末端区域切割釉原蛋白，显示出该酶对切割S/M和F/S键的偏好。釉质溶解素对釉原蛋白的这种活性结果解释了在釉质形成分泌阶段p148（20k）猪釉原蛋白的丰度情况。
