Table 3.
Comparison of MMP-20 peptide library cleavage site selectivity with cleavage sites previously demonstrated to occur in amelogenin. (Upper table) data generated by incubation of enamelysin with mixture-based oriented peptide libraries (see Figure 4) followed by amino acid sequencing. Numbers in the top row are preceded by a “P” to indicate the position of an amino acid relative to the scissile bond between P1 and P1′. Numbers in parenthesizes represent the selectivity value as defined in Figure 4. (Lower table) previously generated data identifying MMP-20 cleavage sites in porcine amelogenin of 173 amino acids in length (38). Numbers in the first column identify the new amelogenin C-terminus after cleavage by MMP-20. Amino acids in bold and underlined were selected by the mixture-based oriented library as promoting hydrolysis of the scissile bond.
| Amino Acid Position | P3 | P2 | P1 | P1′ | P2′ | P3′ |
|---|---|---|---|---|---|---|
| A (2.4) | H (2.5) | S (3.2) | L (4.1) | R (1.6) | A (2.1) | |
| P (2.0) | Y (1.8) | Q (1.8) | M (3.1) | T (1.6) | S (2.0) | |
| V (1.4) | Q (1.5) | N (1.7) | Y (3.3) | V (1.4) | T (1.7) | |
| S (1.4) | I (2.1) | |||||
| Demonstrated Enamelysin Cleavage Sites for Porcine Amelogenin | ||||||
| 148 | M | F | S | M | Q | S |
| 147 | P | M | F | S | M | Q |
| 136 | I | Q | P | L | L | P |
| 107 | P | L | P | A | Q | Q |
| 105 | N | L | P | L | P | A |
| 63 | S | H | A | L | Q | P |
| 45 | G | G | W | L | H | H |