Characterization of Actin and Myosin Extracts Obtained Using Two Improved Laboratory Methods

Actin and myosin are the most important contractile proteins in the muscle. Numerous authors developed different methods for isolation and purification of myofibrillar proteins. The aim of this study was to obtain suitable actin and myosin extracts from post-rigor porcine muscle to be used in further studies, such as testing the proteolytic activity of microbial cultures. Actin and myosin were quantified in the extracts using spectrophotometric methods, yielding 0.17 and 0.22 mg/mL, respectively. The isolation methods proposed in this study provided low contaminated extracts, showing purity percentages of 74.36 % in the case of actin and 65.43 % for myosin, as determined by sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Subsequently, these extracts were sterilized through a 0.22-μm polyvinylidene difluoride filter with no significant retention observed. In conclusion, the procedures described in this work for actin and myosin isolation can be recommended for microbiological studies requiring sterilized pure muscle proteins extracts.