@article {5225,
	title = {Reaction of human myoglobin and nitric oxide - Heme iron or protein sulfhydryl (S) nitrosation dependence on the absence or presence of oxygen},
	journal = {Journal of Biological Chemistry},
	volume = {276},
	number = {6},
	year = {2001},
	note = {ISI Document Delivery No.: 401HBTimes Cited: 33Cited Reference Count: 58},
	month = {Feb},
	pages = {3991-3998},
	type = {Article},
	abstract = {The amino acid sequence of human myoglobin (Mb) is similar to other mammalian Mb except for a unique cysteine residue at position 110 (Cys(110)). Anaerobic treatment of ferrous forms of wild-type human Rib, the C110A variant of human Mb or horse heart Mb, with either authentic NO or chemically derived NO in vitro yields heme-NO complexes as detected by electron paramagnetic resonance spectroscopy (EPR). By contrast, no EPR-detectable heme-NO complex was observed from the aerobic reactions of NO and either the ferric or oxy-Mb forms of wild-type human or horse heart myoglobins, Mass analyses of wild-type human Mb treated aerobically with NO indicated a mass increase of similar to 30 atomic mass units (i.e,, NO/Mb = 1 mol/mol), Mass analyses of the corresponding apoprotein after heme removal showed that NO was associated with the apoprotein fraction. New electronic maxima were detected at A(333) nm (epsilon = 3665 +/- 90 mol(-1) cm(-1); mean +/- S.D.) and A(545) nm (epsilon = 44 +/- 3 mol(-1) cm(-1)) in solutions of S-nitrosated wild-type human Mb (similar to S-nitrosoglutathione), Importantly, the sulfhydryl S-H stretch vibration for Cys(110) measured by Fourier transform infrared (nu similar to 2552 cm(-1)) was absent for both holo- and apo- forms of the wild-type human protein after aerobic treatment of the protein with NO. Together, these data indicate that the reaction of wild-type human Mb and NO yields either heme-NO or a novel S-nitrosated protein dependent on the oxidation state of the heme iron and the presence or absence of dioxygen.},
	keywords = {ELECTRON-SPIN-RESONANCE, GLUTATHIONE, HEMOGLOBIN, HUMAN SKELETAL-MUSCLE, METMYOGLOBIN, NITROSOTHIOLS, OXIDATION, RELAXING FACTOR, SMOOTH-MUSCLE, VASCULAR TONE},
	isbn = {0021-9258},
	url = {<Go to ISI>://000166921200038},
	author = {Witting, P. K. and Douglas, D. J. and Mauk, A. G.}
}
@article {4978,
	title = {Reaction of human myoglobin and H2O2 - Involvement of a thiyl radical produced at cysteine 110},
	journal = {Journal of Biological Chemistry},
	volume = {275},
	number = {27},
	year = {2000},
	note = {ISI Document Delivery No.: 332QGTimes Cited: 55Cited Reference Count: 52},
	month = {Jul},
	pages = {20391-20398},
	type = {Article},
	abstract = {The human myoglobin (Mb) sequence is similar to other mammalian Mb sequences, except for a unique cysteine at position 110. Reaction of wild-type recombinant human Mb, the C110A variant of human Mb, or horse heart Mb with H2O2 (protein/H2O2 = 1:1.2 mol/mol) resulted in formation of tryptophan peroxyl (Trp-OO.) and tyrosine phenoxyl radicals as detected by EPR spectroscopy at 77 K. For wild-type human Mb, a second radical (g similar to 2.036) was detected after decay of Trp-OO. that was not observed for the C110A variant or horse heart Mb. When the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) was included in the reaction mixture at protein/DMPO ratios less than or equal to 1:10 mol/mol, a DMPO adduct exhibiting broad absorptions was detected. Hyperfine couplings of this radical indicated a DMPO-thiyl radical. Incubation of mild-type human Mb with thiol-blocking reagents prior to reaction with peroxide inhibited DMPO adduct formation, whereas at protein/DMPO ratios greater than or equal to 1:25 mol/mol, DMPO-tyrosyl radical adducts were detected. Mass spectrometry of wild-type human Mb following reaction with H2O2 demonstrated the formation of a homodimer (mass of 34,107 +/- 5 atomic mass units) sensitive to reducing conditions. The human Mb C110A variant afforded no dimer under identical conditions. Together, these data indicate that reaction of wild-type human Mb and H2O2 differs from the corresponding reaction of other myoglobin species by formation of thiyl radicals that lead to a homodimer through intermolecular disulfide bond formation.},
	keywords = {ASCORBATE, CROSS-LINKING, enzyme catalysis, HEMOGLOBIN, HYDROGEN-PEROXIDE, LOW-DENSITY-LIPOPROTEIN, METMYOGLOBIN, OXIDATION, SPERM WHALE MYOGLOBIN, SPIN ADDUCTS},
	isbn = {0021-9258},
	url = {<Go to ISI>://000088084500025},
	author = {Witting, P. K. and Douglas, D. J. and Mauk, A. G.}
}
@article {3006,
	title = {DIOXYGEN AND CARBON-MONOXIDE BINDING TO APOLAR CYCLOPHANE HEMES - DURENE-CAPPED HEMES},
	journal = {Journal of the American Chemical Society},
	volume = {116},
	number = {1},
	year = {1994},
	note = {ISI Document Delivery No.: MT212Times Cited: 40Cited Reference Count: 48},
	month = {Jan},
	pages = {6-14},
	type = {Article},
	abstract = {Detailed solution kinetic and equilibria data (mainly in toluene) are presented for the reversible binding of CO and O2 to the five-coordinate hemes Fe(por)B, where B is 1,5-dicyclohexylimidazole or 1,2-dimethylimidazole (chosen to mimic the R- and T-states, respectively) and por = the dianion of some durene-capped porphyrins with variable length linking methylene straps on either side of the durene moiety (4/4, 5/5, or 7/7 methylenes). Use of spectrophotometric equilibrium titrations from 30 to -50-degrees-C, stopped-flow data, and laser flash photolysis under either CO or CO/O2 mixtures, has allowed for determination of on and off rates, equilibrium constants, and, in the case of the 4/4-system, thermodynamic constants for the binding. Increasing steric hindrance provided by the durene cap, in the order 7/7 < 5/5 < 4/4, is generally less than expected from studies with other heme derivatives; in combination with the complete absence of polarity effects, as within nonpolar distal sites, the durene hemes exhibit poor differentiation between CO and O2. However, the distorted 4/4-derivative discriminates between CO and O2 in a novel way through a {\textquoteright}{\textquoteright}proximal effect{\textquoteright}{\textquoteright} associated with deformation of the porphyrin skeleton from planarity, the effect being largely reflected by an increased CO dissociation rate.},
	keywords = {BINDING, CO, CRYSTAL-STRUCTURE, FREE-BASE, HEMOGLOBIN, IRON(II) PORPHYRINS, LIGAND-BINDING, O-2, O2 BINDING, SPERM WHALE, T-STATE},
	isbn = {0002-7863},
	url = {<Go to ISI>://A1994MT21200002},
	author = {David, S. and James, Brian R. and Dolphin, D. and Traylor, T. G. and Lopez, M. A.}
}
