The effect of pH on the affinities of enzymes for substrates and inhibitors

Inhibition of enzymically active N‐acetyl‐homocysteinyl‐ribonuclease by silver ions

“…2. The experimental points are joined by a curve constructed according to Dixon's method [7]. As indicated by the intersection point of the projected straight lines, an ionising group with pK, = 6.2 is responsible for the observed pH dependence.…”

Chemical Modification and Kinetic Studies on Glucarate Hydro‐Lyase from a Species of Pseudomonas A

“…The residue was allocated a role in the catalytic site by modification with diazotised 5-amino-lH-tetrazole, a non-specific coupling reagent which will modify amino acid residues as different as glutamate and lysine [13]. However actual identification of the residue at this stage in the understanding of the enzyme mechanism will not affect the mechanism outlined in Fig.7.…”

“…The various symbols refer to the different buffers used over the pH range 6.0-9.5: 0, succinate; 0 , phosphate; A , Tris-HC1 and 0, glycine 0 some of its properties. A useful method for determining the pK values of amino acid residues in proteins has been described by Dixon [13]. He has formulated a set of rules which enables interpretations of the variation of Km, Ki and V to be made.…”

On the mechanism of amide bond cleavage catalyzed by aminopeptidase M. Enzymatic properties of nitroaminopeptidase M

“…Apparently the method of Dixon [7] will always give such combined values if there is any neighboring group cooperativity. After nitration a small pK shift (0.35 units) of the individual tyrosine causes a corresponding increase in the nucleophilic character but the enzymatic activity is actually diminished.…”