Sarkissian L K, Nalbandyan R M
Biosci Rep. 1983 Oct;3(10):915-20. doi: 10.1007/BF01140660.
A copper-containing protein resembling in its optical and EPR spectra stellacyanin from latex was isolated from spinach leaves. The protein oxidizes ferrocyanide and catechol. The activity was highest at acidic pH. It was shown that similar proteins isolated from cucumber and squash also possess the oxidase activity to ferrocyanide.