Beef tenderness and intramuscular fat proteomic biomarkers: muscle type effect

Tenderness and intramuscular fat content are key attributes for beef sensory qualities.Recently some proteomic analysis revealed several proteins which are considered asgood biomarkers of these quality traits. This study focuses on the analysis of 20 ofthese proteins representative of several biological functions: muscle structure andultrastructure, muscle energetic metabolism, cellular stress and apoptosis. The relativeabundance of the proteins was measured by Reverse Phase Protein Array (RPPA) infive muscles known to have different tenderness and intramuscular lipid contents:Longissimus thoracis (LT), Semimembranosus (SM), Rectus abdominis (RA), Tricepsbrachii (TB) and Semitendinosus (ST). The main results showed a muscle type effecton 16 among the 20 analyzed proteins. They revealed differences in protein abundancedepending on the contractile and metabolic properties of the muscles. The RA musclewas the most different by 11 proteins differentially abundant comparatively to thefour other muscles. Among these 11 proteins, six were less abundant namely enolase3 (ENO3), phosphoglucomutase 1 (PGK1), aldolase (ALDOA), myosin heavy chainIIX (MyHC-IIX), fast myosin light chain 1 (MLC1F), triosephosphate isomerase 1(TPI1) and five more abundant: Heat shock protein (HSP27, HSP70-1A1, B-crystallin(CRYAB), troponin T slow (TNNT1), and aldolase dehydrogenase 1 (ALDH1A1).Four proteins: HSP40, four and a half LIM domains protein 1 (FHL1), glycogenphosphorylase B (PYGB) and malate dehydrogenase (MDH1) showed the sameabundance whatever the muscle. The correlations observed between the 20 proteinsin all the five muscles were used to construct a correlation network. The proteins themost connected with the others were in the following order MyHC-IIX, CRYAB, TPI1,PGK1, ALDH1A1, HSP27 and TNNT1. This knowledge is important for understandingthe biological functions related to beef tenderness and intramuscular fat content.