Properties of sulfanilazo-haptoglobin.
1. Tyrosine and two structural isomers of histidine residues in human haptoglobin were modified with diazotized sulfanilic acid. Sulfanilazo-derivatives of haptoglobin obtained by increasing the reagent/protein molar ration showed gradual decrease of peroxidase activity when complexed with hemoglobin. 2. Formation of haptoglobin derivatives with ten mono(sulfanilazo)-tyrosines and two mono (sulfanilazo)histidines resulted in the blockage of one out of six antigenic determinants, whereas immunoreactivity of the derivative with fourteen azotyrosines, one C-4, and two C-2 azohistidines was decreased by half. 3. Removal of sialic acid from oligosaccharide chains of haptoglobin made the molecule more accessible to diazotized sulfanilic acid. 4. Sulfanilazo-modification of tyrosine and histidine residues was practically of no effect in the reaction of haptoglobin with plant lectin, concanavalin A.
Dobryszycka
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W
Department of Pharmaceutical Biochemistry, Medical Academy, Wroclaw, Poland.
Guszczyński
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T
D006242:Haptoglobins / Q000378:metabolism*; D006639:Histidine / Q000378:metabolism*; D006801:Humans; D013424:Sulfanilamides / Q000032:analysis*; D014443:Tyrosine / Q000378:metabolism*
D006242:Haptoglobins; D013424:Sulfanilamides; D014443:Tyrosine; D006639:Histidine