Q&A: Cooperativity
نویسنده
چکیده
What is the importance of cooperativity? That depends on the system, but let’s take hemoglobin. Hemoglobin’s mission is to pick up a large amount of oxygen in the lungs, where the oxygen concentration (or partial pressure) is about 100 torr, and then drop off a good fraction of it in the peripheral tissues where the oxygen concentration is about 20 torr. Cooperativity helps make this transport efficient.
منابع مشابه
N- and P/Q-type Ca2+ channels mediate transmitter release with a similar cooperativity at rat hippocampal autapses.
The relationship between extracellular Ca2+ concentration and EPSC amplitude was investigated at excitatory autapses on cultured hippocampal neurons. This relationship was steeply nonlinear, implicating the cooperative involvement of several Ca2+ ions in the release of each vesicle of transmitter. The cooperativity was estimated to be 3.1 using a power function fit and 3.3 using a Hill equation...
متن کاملQuestion & Answer Q&A: Cooperativity
What is the importance of cooperativity? That depends on the system, but let’s take hemoglobin. Hemoglobin’s mission is to pick up a large amount of oxygen in the lungs, where the oxygen concentration (or partial pressure) is about 100 torr, and then drop off a good fraction of it in the peripheral tissues where the oxygen concentration is about 20 torr. Cooperativity helps make this transport ...
متن کاملCooperativity in biological systems
Living organisms can sense and respond to external and internal stimuli. Response isdemonstrated in many forms including modulation of gene expression profiles, motility,secretion, cell death, etc. Nevertheless, all forms share a basic property: they depend on sensingsmall changes in the concentration of an effector molecule or subtle conformational changes ina protein and invoking the appropri...
متن کاملNew Sequential Model for Human Hemoglobin: Alpha Subunit as Cooperativity Inducer
Hemoglobin is a tetrameric oxygen transport protein in animal bodies. However, there is a paucity of information regarding differences between alpha and beta subunits of hemoglobin in terms of oxygen affinity. The sequential model of Koshland, Nemthy and Filmer (KNF model) has attributed similar affinities to both alpha and beta subunits. The main purpose of the present study is to construct a ...
متن کاملCondensation of polynucleosome by histone H1 binding.
The cooperative binding of histone H1 to polynucleosome was studied quantitatively. The equilibrium and kinetic data were satisfactorily described in terms of the large ligand model. The binding constant K and the cooperativity parameter q showed remarkable salt effects: K = 7.5 X 10(7) M-1 and q = 1.3 X 10(4) at 0.2 M NaCl, pH 7.5 and 20 degrees C. This considerably strong cooperativity reveal...
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عنوان ژورنال:
- Journal of Biology
دوره 8 شماره
صفحات -
تاریخ انتشار 2009