Figure 4. Gelatin (a) and casein (b) zymograms for ESEF (1), predentin (2), dentin (3), and HME (4) samples prepared from the porcine permanent tooth germs. The electrophoresed gels were incubated with 2 mM Ca (+) or 2 mM EDTA (-). The EDTA chelates metal ions and inactivates matrix metalloproteinases. The volumes of these samples applied to wells were almost the same as that of the neutral-soluble fraction of the inner layer enamel sample as shown in Fig. 3.