A Judgment on Postmortem Aging inLongissimus DorsiBased on a Peptide Substrate Library

Abstract

We attempted to develop a method to determine easily and effectively the degree of postmortem aging of pork longissimus dorsi (LD) by measuring the activity of proteases in the LD using fluorogenic peptide substrates. LD was used to measure the change with time in the protease activity detected with these substrates. Determining the variations within the LD muscles, strong positive correlations were found between changes in hardness and fluorescence intensities against Ac-Ala-MCA, Ac-Met-MCA, Ac-Ser-MCA, Ac-Thr-MCA, and Ac-Ala-Phe-MCA (P < 0:005), and strong negative correlations were found between changes in total amounts of free amino acids and Ac-Ala-MCA, AcMet-MCA, Ac-Ser-MCA, Ac-Thr-MCA, and Ac-AlaPhe-MCA (P < 0:001). Negative correlations were also observed between changes in the amounts of free Ala, Arg, Lys, Leu, Met, Phe, and Tyr and the fluorescence intensities against Ala, Arg, Lys, Leu, Met, Phe, and Tyr-MCA respectively (P < 0:001).

Aromatic capping surprisingly stabilizes furan moieties in peptides against acidic degradation

“…For C-terminal labeling the carboxylic group can be left to react with a fluorophore amine group such as aminocoumarin using a variety of coupling reagents. [5][6][7][8] However, low yields have been observed due to the reduced nucleophilicity of aromatic amines, and epimerization seems to be a severe problem. As for the internal labeling of peptides, mostly the natural available nucleophilic functionalities are used.…”