Quentin H. Gibson

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The effects of mutagenesis on geminate and bimolecular O2 rebinding to 90 mutants at 27 different positions were used to map pathways for ligand movement into and out of sperm whale myoglobin. By analogy to a baseball glove, the protein "catches" and then "holds" incoming ligand molecules long enough to allow bond formation with the iron atom. Opening of(More)
Oxygen equilibrium curves of the purified hemoglobin component I from the Atlantic bluefin tuna (Thunnus thynnus) have been determined between pH 6.5 and 8.75 at 25 degrees C, and for five temperatures between 10 and 30 degrees C at pH 7.0 and 7.5. From the equilibrium data oxygen equilibrium constants for four oxygenation steps, Ki (i = 1 to 4) were(More)
Although spectrophotometric determinations of steady states together with turnover rates have allowed Chance (1952) to calculate that the rate of reaction of reduced cytochrome oxidase with oxygen must be about 107M-1 sec.-', no direct measurements of this rate appear to have been reported. This is due to the difficulty of obtaining the enzyme in a form(More)
Hydrogen peroxide reacts with ferrous horseradish peroxidase and converts it to oxyperoxidase in a sequence of two reactions. The first is the reaction of ferrous peroxidase with HzOz to form Compound II; the second is the reaction of Compound II with HzOz to form oxyperoxidase. Both reactions follow second order kinetics, being first order with respect to(More)
A quadruple mutant of sperm whale myoglobin was constructed to mimic the structure found in Ascaris suum hemoglobin. The replacements include His(E7)-->Gln, Leu(B10)-->Tyr, Thr(E10)--> Arg, and Ile(G8)-->Phe. Single, double, and triple mutants were characterized to dissect out the effects of the individual substitutions. The crystal structures of the deoxy(More)