5N-HSQC:Titration of Unlabelled Peptide into Labelled Protein 1:0 1:01 1:0.3 1:0.5 1:1.0 15N-HSQC:Titration of Unlabelled Peptide into Labelled Protein 1:01 103 1:1.21:1.0 1:0.5 1:0.3 1:0.1 1:0 Intermediate Fast/ Intermediate Fast Slow? 15N-HSQC: Titration of Unlabelled Peptide into Labelled Protein 1:1.2 1:1.0 1:0.5 1:0.3 1:0.1 1:0 Intermediate Fast/ Intermediate Fast Intermediate? 15N-HSQC: Titration of Unlabelled Peptide into Labelled Protein