The intensity of myosin heavy chain (MHC) bands was NaNO2-dose
dependent, decreasing on days 0 and 7 (Fig. 2 A & B). MHC was reduced
and converted into protein polymers. The intensity of myosin bands was
mostly recovered when MP were treated with β-ME (Fig. 2 A & B). This
suggested that the disulfide bonds were mainly responsible for the presence
of the polymers on days 0 and 7. However, a portion of MHC bands
were not recovered especially on days 14 and 21 (Fig. 2 C & D), which
may be due to the formation of other covalent bonds, such as distyrosine
and active carbonyl–NH2 interactions. The formation of covalent bonds
was supported by the loss of both carbonyls and free amines (Fig. 1 A &
B).