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THE HAEM‐ACCESSIBILITY IN LEGHAEMOGLOBIN OF LUPINUS LUTEUS AS OBSERVED BY PROTON MAGNETIC RELAXATION

1976; Wiley; Volume: 8; Issue: 5 Linguagem: Inglês

10.1111/j.1399-3011.1976.tb02522.x

0367-8377

S. Vuk‐Pavlović, Bojan Benko, Siniša Maričić, G. Lahajnar, И. П. Куранова, B. K. Vaĭnshteĭn,

Advanced NMR Techniques and Applications

Using the solvent‐protons' longitudinal magnetic relaxation rates (p.m.r.) for Lupinus luteus leghaemoglobin derivatives the accessibility of the haem has been evaluated by our “stereo‐chemical p.m.r. titration” method with nonexchangeable protons of aliphatic lower alcohols in otherwise deuterated solutions. The haem in leghaemoglobin is more accessible and its protein environment more flexible compared with vertebrate haemoglobins. The correlation time in aquometleghaemoglobin aqueous solution has been determined by measuring the frequency dispersion of the p.m.r. rates between 6.1 and 93 MHz. Taking into account the measured value of τ c = (7.7 ± 0.5) × 10 ‐10 s the iron‐to‐proton inter‐spin distances have been calculated. The significance of these distances as well as the electronic g‐factor anisotropy for elucidation of fine structural details of the haem‐environment are discussed.