Leucine aminopeptidase of bovine lens is a zinc metallo-enzyme. A zinc content of 5.0 - 7.6 g-atoms of Zn/M.W. 3.2 x 10(6) was estimated by labelling with 65Zn and by atomic absorption spectrophotometry. By continuous dialysis against o-phenanthroline zinc was almost completely removed. The enzymatically inactive "apo"-enzyme could not be reactivated by addition of Zn(2+). The binding of cadmium, manganeous and cobaltous ions was investigated. With some probability manganese is bound at an other site than zinc. The effect of pH and buffer ions on the binding of zinc to leucine aminopeptidase was demonstrated.
Kettmann
Ursula
U
Physiologisch-chemisches Institut der Martin-Luther-Universität, Halle/Saale, GDR
Hanson
H
H
Zur Bedeutung des Zinks in der Leucinaminopeptidase aus Rinderaugenlinsen.