Ayşe KARAGÖLGE, Yaşar DEMİR, Nazan DEMİR, İrfan KÜFREVİOĞLU

Apocarbonic anhydrase-enzymatic determination of zinc in fruit juices

In this study, a new enzymatic method for determining trace amount of zinc was employed on ten different fruit juices. The basis of the enzymatic method is that apocarbonic anhydrase regains its activity in proportion to the $Zn^{2+}$ existing in a solution. Thus, the more activated the enzyme is in the medium, the higher the $Zn^{2+}$ concentration in the solution will be. For this purpose, bovine carbonic anhydrase was purified from erythrocyte hemolisate by affinity chromatography. The $Zn^{2+}$ bound to the enzyme was removed by of the purified enzyme against the solution of pyridine-2-6-dicarboxylic acid. Thus 100% purified enzyme was obtained. First, the presence of $Zn^{2+}$ in the fruit juices sample was determined by the enzymatic method. Then the content of $Zn^{2+}$ in the same sample was measured by atomic absorption spectroscopy. According to the results obtained, the enzymatic method that we have developed is a variable means of determining.

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