Abstract:

This study aimed to find the optimum extraction conditions for metmyoglobin reductase (MetMbR) from
longissimus dorsi muscle of yak. The selection of extraction buffer and the optimization of important extraction parameters
for enhanced MetMbR activity were carried out by combined use of single factor method and response surface methodology.
PBS buffer was found to be the most suitable for the extraction of MetMbR. The pH and concentration of PBS buffer, and
solid-to-solvent ratio were identified as main extraction parameters, and their importance showed a decreasing order of
pH > solid-to-solvent ratio > concentration. The optimum extraction conditions were determined as extraction using
2.12 mmol/L PBS buffer (pH 7.22) with a solid-to-solvent ratio of 1:2.25 (m/V). Under these conditions, the metmyoglobin
reductase activity was 73.92 U/L, which coincides with the theoretical value with a relative error of 0.86%. In conclution,
the model developed in this study is feasible in practice.

Key words: metmyoglobin reductase, longissimus dorsi muscle of yak, extraction process, response surface methodology