the human rhinovirus receptor with a monoclonal antibody that inhibits rhinovirus binding to cells b immunoprecitation of purified 125 i labeled receptor with the atcc hb 9594 monoclonal antibody 5 a tryptic fragment was prepared by digesting the receptor with 1 wt e wt receptor protein trypsin for 1 hour at 37 u00b0 c the reaction mixture was applied to a gf 450 gel filtration column dupont equilibrated in n buffer and the proteolytic fragment separated from the enzyme analysis of the resultant fragments by sds page indicated a mixture of a 90 000 dalton and an 83 000 dalton fragment of the receptor these fragments eluted in the same position on a gel filtration column as intact receptor suggesting that it is bound to a detergent micelle amino acid sequencing of the fragments yielded no sequence indicating that they like the intact receptor have a blocked n terminus and further indicating that peptides lost from the 90 000 and 83 000 dalton fragments are from the c terminus of the protein 1 the purity of the receptor preparation was assessed by sds page followed by silver staining quantitation of protein was determined by comparing silver stained protein with a series of standard proteins of known amount on sds page and confirmed by amino acid analysis assuming a protein molecular weight of 50 000 daltons determined by determining the apparent molecular weight on sds page of deglycosylated receptor 2 the protein was shown to be a glycoprotein containing 6 7 asparagine linked oligosaccharide chains by digestion of core glycosylated receptor with endoglycosidase h upon gel filtration the receptor eluted with a volume consistent with.