TY - JOUR
T1 - Iron‐Nitrosyl Bond Configuration in Nitrosyl‐Hemoproteins
T2 - A Comparative EPR Study of Hemoglobin A and Hemoglobin Kansas
AU - Chevion, M.
AU - Salhany, J. M.
AU - Peisach, J.
AU - Castillo, C. L.
AU - Blumberg, W. E.
PY - 1976
Y1 - 1976
N2 - Hemoglobin A and hemoglobin Kansas can exist in alternative forms in which the affinity of heme iron for NO is mediated either by pH or the presence of allosteric modifiers. In this study, we show that the superhyperfine (SHF) pattern observed in the EPR which arises from the heme iron‐NO complex can be correlated with a change in the affinity of the ligated tetrameric protein for NO. When a combination three‐line and nine‐line SHF pattern is observed, the nitrosyl hemoprotein is in a low affinity form while a nine‐line pattern alone is an expression of high affinity. A theory is presented relating SHF patterns to a molecular orbital picture of the nitrosyl heme complex. It is suggested that the change of SHF pattern correlated with an alteration of the affinity state of ligated hemoglobin is related to a structural change of the proximal imidazole ligand to the heme.
AB - Hemoglobin A and hemoglobin Kansas can exist in alternative forms in which the affinity of heme iron for NO is mediated either by pH or the presence of allosteric modifiers. In this study, we show that the superhyperfine (SHF) pattern observed in the EPR which arises from the heme iron‐NO complex can be correlated with a change in the affinity of the ligated tetrameric protein for NO. When a combination three‐line and nine‐line SHF pattern is observed, the nitrosyl hemoprotein is in a low affinity form while a nine‐line pattern alone is an expression of high affinity. A theory is presented relating SHF patterns to a molecular orbital picture of the nitrosyl heme complex. It is suggested that the change of SHF pattern correlated with an alteration of the affinity state of ligated hemoglobin is related to a structural change of the proximal imidazole ligand to the heme.
UR - http://www.scopus.com/inward/record.url?scp=84987359683&partnerID=8YFLogxK
U2 - 10.1002/ijch.197600053
DO - 10.1002/ijch.197600053
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AN - SCOPUS:84987359683
SN - 0021-2148
VL - 15
SP - 311
EP - 317
JO - Israel Journal of Chemistry
JF - Israel Journal of Chemistry
IS - 3-4
ER -