Fractionation of type V collagen from carcinomatous and dysplasic breast in the presence of alkaline potassium chloride

A simple, one-step fractionation technique suitable for the finest quantitation of type V collagen from acidic mixtures of interstitial collagens is reported. The technique is based on the higher solubility of this collagen type in alkaline KCl-phosphate solution, and the purity of the sample has been monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electron microscopic analyses. The latter reveal that the majority of the molecules are endowed with a thread portion and a terminal knob, and show a low tendency to originate ordered and reproducible polymers at low temperature.