Peroxidase isoenzymes of the Avena coleoptile

The bulk of the peroxidases of Avena coleoptile sections exist in soluble and salt-extractable, wall-associated fractions with lesser amounts in membranous and wall-bound fractions. In the presence of auxin the peroxidase levels remain nearly constant while in the absence of auxin the peroxidase of each fraction increases 2-to 6-fold in 22 hr. There are qualitative and quantitative changes in the isoenzyme patterns with time, but these changes are independent of auxin. It is concluded that the peroxidase changes are induced by isolation of the tissues from the coleoptile and are unrelated to the growth rate.