A PROTEASE-LIKE PERMEABILITY FACTOR IN GUINEA-PIG SKIN - CONTACT ACTIVATION OF THE LATENT PERMEABILITY FACTOR AND ITS NATURE AS A PREKALLIKREIN ACTIVATOR

Abstract

A proteaselike permeability factor in guinea pig skin, which was fractionated in a latent form into pseudoglobulin fraction, was activated by contact with kaolin particles at neutral pH. This contact activation was not prevented by the presence of 1 M KCl, and was strongly inhibited by the simultaneous presence of hexadimethrine bromide. The latent permeability factor was 1st bound to kaolin; later an active form permeability factor was released from the kaolin-bound parent molecule. Prekallikrein activator activity was generated in this supernatant from the pretreatment kaolin particle in the same time course as the permeability factor generation. The prekallikrein activator and permeability factor were observed at the same fractions in every purification step with DEAE cellulose column chromatography, Sephadex G-75 gel filtration and isoelectric focusing. These 2 molecules are identical. Apparently the latent permeability factor in the guinea pig skin has properties similar to those of the plasma Hageman factor.