This project aims to deepen the study of structural and functional characteristics of calpain and calpastatin proteins in Nelore (Bos indicus) from production selected herd, and their relation to the meat quality, specifically tenderness. The calcium-dependent proteolytic system called calpain-calpastatin is considered as a limiting factor in the myofibrillar proteins (protein turnover) synthesis and degradation. Thus, knowledge about this enzyme system allow it's manipulation, which can result in changes on myofibrillar proteins growth and degradation rate. For the experimental analysis about 2,000 Nelore (Bos indicus) will be used, feedlot finished with age less than two years, with available information about performance and pedigree. From the amount of 2000 slaughtered animals, 40 Nelore, divided into two experimental treatments, will be used for this test: (1) animals with the highest shear force values (n = 20) and (2) animals with the lowest shear force values (n = 20), in order to get two quite contrasting groups on the meat tenderness. Between all samples, one will be used for the shear force test (SF), another one for LM area, one for backfat thickness and finally one for marbling score. The remaining samples will be used for total lipid analysis, meat instrumental color and myofibrillar fragmentation index (MFI). Proteomics will be used to visualize differences in expression of these proteins related to environmental conditions and processing. Electrophoretic separations will be performed in two-dimensional gels (2D) electrophoresis system using a 2D PAGE. The mapping of calcium in protein spots will be done in the line of X-ray fluorescence with synchrotron radiation (SR-XRF). The protein spots will be identified by MALDI-TOF MS (matrix-assisted laser desorption ionization time of flight mass spectrometry).
News published in Agência FAPESP Newsletter about the scholarship: