Determination of spin state equilibria in Fe(III)-hemeproteins by magnetic circular dichroism

Conference · Sun Feb 01 04:00:00 EST 1976

OSTI ID:7286202

Vickery, L E

The intensity of the magnetic circular dichroism (MCD) associated with the near-uv Soret transition of ferric hemeproteins is paramagnetic in origin and is proportional to the amount of low spin (S = /sup 1///sub 2/) component present. For characterization of low spin reversible high spin (S = /sup 5///sub 2/) mixtures the MCD technique can offer advantages over other methods: samples need not be pure if other components present exhibit weaker magneto-optical activity than the intense hemeprotein signals, high sensitivity allows for low (..mu..m) concentrations to be used, measurements can be obtained at physiological as well as cryogenic temperatures and thermodynamic parameters can be determined, and rapid kinetic measurements should be possible. Results obtained with a variety of hemeproteins (myoglobin, hemoglobin, cyt. c, cyt. f, cyt. b/sub 5/, cyt. P-450, cyt. oxidase, and hemopexin) are described to illustrate the utility of MCD as a spectral probe for monitoring spin state equilibria both in vitro and in situ.

• Research Organization: California Univ., Berkeley (USA). Lawrence Berkeley Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7286202
• Report Number(s): LBL-4687; CONF-751180-1
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ANGULAR MOMENTUM
BIOCHEMICAL REACTION KINETICS
CARBOXYLIC ACIDS
DICHROISM
EQUILIBRIUM
GLOBIN
HEME
HEMOGLOBIN
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
IRON COMPOUNDS
KINETICS
MAGNETIC FIELDS
MYOGLOBIN
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PARTICLE PROPERTIES
PHYSICAL PROPERTIES
PIGMENTS
PORPHYRINS
PROTEINS
REACTION KINETICS
SPECTRA
SPIN
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS