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Biomedical subjects

H Blum

Publications and source records attributed to H Blum.

At least 91 records · Page 5Linked to original sources
PubMed1978

The orientation of a heme of cytochrome c oxidase in submitochondrial particles.

The electron paramagnetic resonance of the low spin signal from oxidized cytochrome c oxidase has been studied in oreinted multilayers of submitochondrial and electron transport particles. Measurements of the angular variation of the EPR spectra with the multilayer plane orientation allow the determination of the heme orientation in the multilayer. The heme normal lies in the membrane plane and the y-axis of the heme makes an angle of 30 degrees with the membrane normal. Analysis of the line shape reveals the presence of mosaic spread in the multilayer almost half of which is attributable to deviations of protein orientation within the membrane.

Animals↗
PubMed1977

Determination of the exchange integral in binuclear iron-sulfur clusters in proteins of varying complexity.

The coupling constants J between the iron atoms in ferredoxin type iron-sulfur proteins containing binuclear clusters were evaluated by two parallel methods. The temperature dependence of the EPR linewidths and integrated abosrption intensities are both related to the energy of the first excited state. The values of J obtained were: center S-1 in succinate dehydrogenase, 90 cm-1; Rieske's iron-sulfur center, 65 cm-1; adrenodoxin, 270 cm-1. The behavior of iron-sulfur center N-1a in NADH:UQ reductase was also examined; its similarity to that of center S-1 indicates that center N-1a is also a binuclear iron-sulfur center, with J = 90 cm-1. Greater rhombic distortion present in the EPR spectrum of a binuclear cluster was associated with smaller values of J.

Adrenodoxin↗