Figure 6.

Analysis of cooperativity in Ca²⁺ binding to CaM fragments and full CaM molecules. Ca²⁺ binding to scallop testis CaM N- and C-terminal domains (A) as well as full length CaM (D) was measured by flow dialysis in [12]. The Scatchard plots for N-terminal (B), C-terminal (C) domains, and full length CaM (E) suggest that Ca²⁺ binding sites are cooperatively bound in pairs within the N- and C- terminal globular domains. r is the number of mol of bound Ca²⁺ per mol of CaM [12]. K₁ and Kc₁ are the dissociation and cooperative dissociation constants for the N-terminal, while K₂ and Kc₂ are the dissociation and cooperative dissociation constants for the C-terminal of scallop testis CaM.