Figure 2.

Prevention of the formation of disulfide cross-links by phosphorylation of PLN or the addition of 10 mM Ca²⁺. (A) Cross-linking was carried out in the absence of the oxidant, as described in the legend to Fig. 1, except that PLN in the microsomal fractions was phosphorylated by PKA before cross-linking was initiated. (B) Cross-linking was carried out in the presence of the oxidant, as described above, except that 10 mM CaCl₂ was present in the reaction mix.