FIGURE 4.

LC-MS analysis of peptic derivatives of DES in the elastin hydrolysate released by pseudoalterin. A, mass spectrum of DES standard. DES standard was prepared in 0.01 m HCl at a final concentration of 2 mg/ml, treated with an equal volume of 4% sulfosalicylic acid, and loaded onto LC-MS. B, mass spectrum of elastin hydrolysate. Twenty milligrams of bovine elastin was degraded by 20 μg of pseudoalterin at 25 °C for 36 h followed by addition of 500 μl of 4% sulfosalicylic acid to remove the long peptides. After centrifugation, the sample was lyophilized and redissolved in 50 μl of 0.01 m HCl and was then detected using the same method as described for the DES standard.