Partial characterization of RC-13, a homogeneous fraction isolated from castor bean allergens (CB-1A).
Allergen RC-13's amino acid composition was determined-Lys3, His1, Arg7, Asp6, Thr2, Ser11, Glu29, Pro2, Gly7, Ala4, Cys6, Val5, Met1, Ile3, Leu3, Tyr1; 91 residues. Partial specific volume and minimum molecular weight evaluated from this composition were, respectively, 0.694 cm3/g and 10,194. SDS-polyacrylamide gel electrophoresis performed in the reduced and alkylated form of the allergen revealed a single band, suggesting the existence of only one polypeptide chain in the molecule. Results obtained for carbohydrate analysis by gas-liquid chromatography were: 22.2% galactose and 16.2% mannose--approximately 38% of neutral sugars. Employment of the amino acid methodology for analysis of amino sugars revealed two residues of glucosamine per molecule of the allergen. Hydrolyses with trypsin, alpha-chymotrypsin and type VII protease were tested for sequence studies. Trypsin was considered a suitable enzyme for such purpose.
Silva Júnior
J G
JG
Departamento de Bioquímica, Universidade Federal do Rio de Janeiro, RJ.
Garcia
M A
MA
Machado
O L
OL
Domont
G B
GB
D000485:Allergens / Q000302:isolation & purification*; D000596:Amino Acids / Q000032:analysis*; D002367:Ricinus communis; D004591:Electrophoresis, Polyacrylamide Gel; D010449:Peptide Mapping; D010947:Plants, Toxic; D012278:Ricinus
D000485:Allergens; D000596:Amino Acids