Simultaneous Determination of Metallothionein and Thionein
نویسنده
چکیده
Metallothionein (MT) has a dynamic role in cellular zinc metabolism. In order to determine the apoprotein thionein (T), an assay was developed. With this method tissue homogenates were treated with subtilisin to digest any T that might exist but MT could not be digested by subtilisin. MT was detected by cadmium-hemoglobin saturation method and T was determined as the difference of MT between samples with and without subtilisin added. With this assay the value of T/MT was found as 0.67, 0.53, 0.14 and 0.10 in four different hamster tissues brain, testis, liver and kidney, individually. This finding was confirmed by gel filtration experiments of liver homogenate supernatants. Upon addition of zinc to the homogenate, zinc in MT containing fractions increased about 2.5 fold. Since the tenet has been that the steady state concentration of T in cells is very low due to its rapid proteolytic digestion, the existence of T under normal physiological condition is a novel finding that has important implications for the function of this protein in zinc metabolism. [The Journal of American Science. 2005;1(1):28-33].
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