Cm. Rosell et al., MYOGLOBIN AS AN ENDOGENOUS INHIBITOR OF PROTEOLYTIC MUSCLE ENZYMES, Journal of agricultural and food chemistry, 44(11), 1996, pp. 3453-3456
The effect of myoglobin content on the activity of different proteolyt
ic systems, lysosomal enzymes, calcium dependent neutral proteinases,
and aminopeptidases was examined concretely. Increasing myoglobin cont
ent inhibited cathepsin activities (B, B + L, and H). A similar effect
was obtained with mu-calpain, which showed about 10% of its initial a
ctivity in the presence of 1 mg/mL of myoglobin. In contrast, m-calpai
n and calpastatin were almost insensitive to different levels of myogl
obin in the medium. Exopeptidases, aminopeptidase B and alanyl aminope
ptidase, were inhibited by myoglobin to approximately the same extent
as the cathepsins. These results suggest that myoglobin might be consi
dered an endogenous inhibitor, which could affect the endogenous prote
olytic activity differently in different types of muscles. Consequentl
y, the rate of both meat tenderization and generation of free amino ac
ids may also be regulated by myoglobin.