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The Reaction of Methemoglobin with Some Ligands

1969; Elsevier BV; Volume: 244; Issue: 17 Linguagem: Inglês

10.1016/s0021-9258(18)93676-8

1083-351X

Quentin Gibson, L.J. Parkhurst, G. Geraci,

Neonatal Health and Biochemistry

Abstract The reaction of methemoglobin with azide and thiocyanate is kinetically complex. The complexity is due to differences in reactivity between the α and β chains, which react independently with azide, each at a characteristic rate. These rates are similar to the rates of reaction of isolated α and β chains with azide. The difference spectra for α and β chains reacting with azide, although similar, are not identical in the Soret region, and these differences can be seen in methemoglobin. Cyanide and fluoride react at the same rate with α and β chains and show a kinetically simple second order reaction with methemoglobin. Nitrite forms a complex with methemoglobin. Its kinetic behavior is like that of azide and thiocyanate, but its affinity for methemoglobin is about 1000 times less than that of azide.