Spectral and other studies on the intestinal haem receptor of the pig

Abstract The receptor was solubilized from brush borders using Triton X-100. Binding of hemin at pH 7.5 caused a shift of the absorption maximum from 395 nm, making difference spectroscopy a suitable method to detect the receptor e.g. in gel filtration, where use of radioactive heme and spectrometry gave the same results. Spectrometry gave a K d of 10 -9 M for the heme-complex dissociation. Trypsin destroyed the receptor.