Isolation and partial characterization of the allergen in mountain cedar pollen.

A biologically active fraction from a crude extract of mountain cedar pollen has been purified and partially chemically characterized. An ammonium bicarbonate extract of commercial defatted pollen was fractionated by G-100 Sephadex chromatography and the biologically active fraction was found to be homogeneous by polyacrylamide gel electrophoresis and N-terminal amino acid sequence analysis. The biologically active component is a 50,000 dalton protein whose N-terminal amino acid sequence is Asp--Asn--Pro--Ile--Asp. These findings provide a further purified pollen allergen for immunologic studies and the first such purified allergen having clinical significance in a limited geographic region.