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Proteolytic activity of opossum tooth extracts
1University of Texas School of Dentistry, Health Science Center at San Antonio, Department of Pediatric Dentistry, 78284-7888, USA.
European Journal of Oral Sciences
|April 16, 1998
Summary
Opossums retain uncleaved amelogenins in developing enamel, unlike placental mammals. This suggests significant differences in enamel matrix protein processing between metatherian and eutherian mammals.
Area of Science:
- Biochemistry
- Developmental Biology
- Evolutionary Biology
Background:
- Amelogenins are the primary proteins in developing tooth enamel.
- In placental mammals, amelogenins are quickly broken down after secretion.
Purpose of the Study:
- To investigate the processing of amelogenins in opossums compared to placental mammals.
- To identify differences in enamel matrix proteinases between metatherian and eutherian mammals.
Main Methods:
- High-performance liquid chromatography (HPLC) fractionation of tooth extracts.
- SDS-PAGE and Western blot analysis.
- Mass spectrometry and amino acid composition analysis.
- Enzymogram analysis using various protein substrates.
Main Results:
- Opossum tooth extracts showed a simple HPLC profile with a single major peak.
- Opossum amelogenin primarily consisted of uncleaved forms (Op202 and Op57) at 28 kDa.
- Placental mammal extracts displayed complex profiles with numerous amelogenin cleavage products.
- Opossum extracts indicated fewer active proteinases compared to porcine and rat extracts.
Conclusions:
- Opossums exhibit significantly different amelogenin processing, retaining uncleaved forms in developing enamel.
- This contrasts with the rapid cleavage observed in placental mammals.
- These findings highlight distinct proteolytic mechanisms in enamel formation between metatherian and eutherian mammals.