Tris: an allosteric effector of tarantula haemocyanin

FEBS Letters

Decker, H.¹  Bardehle, K.¹  Sterner, R.¹  Paul, R.¹ 

[1] Zoologisches Institut der Universität München, Luisenstr. 14, D-80333 München 2, Germany

关键词: Allostery;    Chloride effect;    Haemocyanin;    Nesting model;    Oxygen binding;    Tarantula;    Tris;   

DOI  :  10.1016/0014-5793(94)80379-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The effect of the chemical buffering component Tris (hydroxy-methyl-amino-methane) and of chloride ions on the oxygen binding of tarantula hemocyanin was studied at constant pH. It revealed that Tris at micromolar concentrations decreases the oxygen pressure at half-saturation (P₅₀) by a factor of more than two, whereas chloride does not influence oxygen affinity. A thermodynamic analysis in terms of the nested model of allostery [(1987) Proc. Natl. Acad. Sci. 84, 1891-1895] indicated that Tris acts a an allosteric activator of oxygen binding by influencing the interaction between the 12-meric half-molecules of the 24-meric tarantula haemocyanin.

【 授权许可】

Unknown