Figure 11.

Assay for CaM isoforms required for NtCaMK1 phosphorylation. Histone IIIs (A) or syntide-2 (B) as substrates were phosphorylated with NtCaMK1 (0.2 μg μL⁻¹) in the presence of NtCaM1(▪), NtCaM3(▴), NtCaM13(•), or B-CaM (▾) in our standard phosphorylation conditions, except increasing amounts of NtCaM (10⁻⁹–10⁻⁵ m) at 30°C for 5 min. The data are averages of three determinations done in duplicate. C, NtCaMK1 autophosphorylation (lanes e–h) and substrate phosphorylation using histone IIIs as substrate (lanes a–d) were performed in the presence of Ca²⁺/NtCaM1 (lanes a and e), Ca²⁺/NtCaM13 (lanes b and f), Ca²⁺/NtCaM3 (1 μm; lanes c and g), or Ca²⁺/NtCaM3 (10 μm; lanes d and h) and resolved by SDS-PAGE with discontinuous 8%/20% separating gel.