Standardisation and application of a semi-quantitative SDS-PAGE method for measurement of myofibrillar protein fragments in bovine longissimus muscle

A semi-quantitative SDS-PAGE method was standardised for the routine analysis of myofibrillar protein fragments, 30 and 110 kDa, associated with the meat tenderisation process. Bovine serum albumin was used as an internal standard. Standard curves for purified proteins demonstrated a linear response using this method. Mean analytical recoveries were 95.5 and 102.8% for separation on 7.5 and 15% acrylamide gels, respectively. The ability of the test to measure 30 kDa and 110 kDa fragments independently of sample volumes was demonstrated. Quality control studies showed that levels of 110 kDa protein fragment quantified on 7.5% gels varied by 23.1% within gels and 36.4% between gels. Quantification of 30 kDa protein fragment on 15% gels varied by 7.3% within gels and 7.0% between gels. This thoroughly standardised SDS-PAGE method may be used to measure 30 and 110 kDa bands in extracts of bovine M. longissimus dorsi over the post-mortem ageing period and to evaluate other quantitative methods developed in the future for measurement of the same protein fragments.