The existence of inhibited lysyl oxidase and the presence of multiple forms.

Considerable difficulty in puriying tissue lysyl oxidase has been previously encountered and the cause of this difficulty has now been ascertained. For these studies, we have used blood plasma lysyl oxidase as a model system. Blood plasma has been shown to contain considerable lysyl oxidase activity. The enzyme exists in a partially or completely inhibited state. Homogeneous preparations of the enzyme from the blood have been obtained by two different methods. Method A yields one form of lysyl oxidase while Method B yields three forms of the enzyme. The methods for the purification of the enzyme and some properties of the enzyme and preliminary data on the lysyl oxidase inhibitor will be discussed.