A NEW TECHNIQUE FOR THE ANALYSIS OF PROTEINS THAT DETERMINE MEAT TENDERNESS

CORIA MS; CARRANZA PG; RIVERO MB; ABDALA ME; LUQUE ME; BARRIONUEVO MG; PALMA GA

Tucuman

Congreso; 3ra Reunión de las Sociedades de Biología de la República Argentina.; 2015

Meat quality is one of the most important factors for consumers. Out of all meat traits, tenderness is considered the most important with regard to eating quality. Meat tenderness is determined by myofibrillar, connective and cytoskeletal elements of the muscle structure. Many studies have shown that the calpain system plays a central role in postmortem proteolysis and tendernization. In skeletal muscle, the calpain system consists of two proteases: calpain 1 (CAPN1) and calpain 2 (CAPN2); and a specific inhibitor: calpastatin (CAST). Methods commonly employed to determine the activity of proteases are the Casein Assay, Colorimetry and Casein Zymogram. The casein assay and colorimetry require purification by chromatography. In the zymogram, the proteases are separated into polyacrylamide gels (with casein) under non-denaturing conditions, and visualized as clear bands on a dark blue background after staining due to the proteolysis of the casein. This is a very simple technique. However, until this study, it was not used to determine the activity of CAST. The aim of this work, was to develop a new technique that allows the determination of CAST effectively, reliably and easily. For the determination, the crude extract (CE) was heated, inhibiting protease activity but not the CAST because it is heat resistant. This CE was coincubated with fresh extract, and a conventional zymogram was performed showing the inhibition of the protease activity. The novel assay enables us to determine the CAST inhibitory activity on the protease activity, allowing a reliable evaluation of the association of protein activity with meat tenderness.