Radiation-induced changes of structural and functional properties of human hemoglobin

1989 ◽  
Vol 28 (1) ◽  
pp. 47-58 ◽  
Author(s):  
Z. Szweda-Lewandowska ◽  
M. Puchała ◽  
P. A. Osmulski ◽  
J. Rosin
2016 ◽  
Vol 62 (3) ◽  
pp. 251-258 ◽  
Author(s):  
V.G. Artyukhov ◽  
E.A. Kalaeva ◽  
O.V. Putintseva ◽  
A.I. Polyubez'eva

Human oxyhemoglobin exhibits high resistance to nitroglycerin during incubation of the protein with this compound for 0.3-3 h. Prolonged exposure (24 h) leads to activation of methemoglobin production. In the presence of nitroglycerin hemoglobin molecules undergo rapid oxidation during deoxygenation with formation of methemoglobin as the terminal product of human oxyhemoglobin interaction with nitroglycerin. The scheme of interaction processes of oxyhemoglobin with nitroglycerin in different conditions of oxygen regime is proposed. Partially deliganded hemoglobin plays the leading role in the initiation of hemoglobin oxidation processes.


2004 ◽  
Vol 18 (2) ◽  
pp. 331-338 ◽  
Author(s):  
Mauro Maccarrone ◽  
Almerinda Di Venere ◽  
Guus van Zadelhoff ◽  
Giampiero Mei ◽  
Gerrit Veldink ◽  
...  

Lipoxygenases (Loxs) form a homologous family of non-heme, non-sulfur iron containing lipid-peroxidizing enzymes, which catalyze the dioxygenation of polyunsaturated fatty acids to the corresponding hydroperoxy derivatives. Soybean lipoxygenase-1 (Lox-1) is widely used as a prototype for studying the structural and functional properties of lipoxygenases. Tryptic digestion of soybean Lox-1 is known to produce a 60 kDa fragment, termed “mini-Lox”, which shows enhanced catalytic efficiency and higher membrane binding ability than the native enzyme (M. Maccarrone, M.L. Salucci, G. van Zadelhoff, F. Malatesta, G. Veldink, J.F.G. Vliegenthart and A. Finazzi-Agrò,Biochemistry40(2001), 6819–6827). In this study, we have investigated the stability of mini-Lox in guanidinium hydrochloride (GdHCl) and under high pressure by fluorescence and circular dichroism spectroscopy. The denaturation experiments demonstrate that mini-Lox is a rather unstable molecule, which undergoes a two-step unfolding transition. Both chemical- and physical-induced denaturation suggest that mini-Lox is more hydrated than Lox-1, an observation also confirmed by 1-8 anilinonaphtalene sulphonic acid binding studies. We have also investigated the occurrence of substrate-induced changes in the protein tertiary structure by fluorescence techniques. In particular, eicosatetraynoic acid (ETYA), an irreversible inhibitor of lipoxygenase, has been used to mimic the effect of substrate binding. We demonstrated that mini-Lox is indeed characterized by much larger conformational changes than those occurring in the native Lox-1 upon binding of ETYA. All these findings strongly support the hypothesis that the larger hydration of mini-Lox renders this molecule more flexible and therefore less stable, that on the other hand is probably causing its higher catalytic efficiency.


2001 ◽  
Vol 268 (6) ◽  
pp. 1739-1748
Author(s):  
Aitor Hierro ◽  
Jesus M. Arizmendi ◽  
Javier De Las Rivas ◽  
M. Angeles Urbaneja ◽  
Adelina Prado ◽  
...  

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