Phi value analysis
Phi value analysis, φ {\displaystyle \varphi } analysis, or φ {\displaystyle \varphi } -value analysis is an experimental protein engineering technique for studying structures of the transition state and intermediates in protein folding and conformational changes. The structure of the folding transition state has to be found from kinetic measurements and is not accessible by equilibrium methods such as protein NMR or X-ray crystallography and intermediates are often mobile and partly unstructured by definition.