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. Author manuscript; available in PMC: 2008 Sep 17.
Published in final edited form as: Biochemistry. 2006 Dec 19;45(51):15748–15755. doi: 10.1021/bi061451k

Table 1.

Parameters describing oxygen binding to some mutants

Mutant L Ton Toff rms COTon [O2]50 calc [O2]50 obs n calc n obs
w/t 48,000 10 500 0.0027 0.2 16.6 16.2 1.54 1.47
T72V 5 0 550 0.0051 0.2 0.2 0.3 1.43 1.55
L73M 650,000 11.6 550 0.0014 0.15 31.9 34.3 1.24 1.24
F97L 330 33 47 0.0025 0.5 1.0 1.6 1.16 1.15
I114F 210,000 4.8 200 0.0015 0.2 26.5 34 1.22 1.08

L is the ratio HbT/HbR for deoxyhemoglobin. Ton is the rate of combination of oxygen with T–state hemoglobin, units are μM(dimer) −1seconds−1. Toff units are seconds−1. r.m.s is the square root of the sum of the squares of differences between observed and calculated values of absorbance for all points in an experiment (usually 14000). COTon units as for oxygen. [O2]50 is the concentration of oxygen (μM) required to give half-saturation using the kinetic parameters listed in the allosteric model. n is Hill’s n, a measure of sigmoidicity. For a dimer its limits are 1, no cooperativity, and 2, full cooperativity. Note that due to experimental error, the results of individual experiments given in the text may not agree with the averaged values of the Table.