Reaction of glutaraldehyde with human erytrocytes.

The reaction of glutaraldehyde with human erythrocytes has been studied at pH values of 6.0, 7.2 and 8.0 at several glutaraldehyde concentrations, for different periods at 37 degrees C. Increasing pH and reagent concentration favours formation of cells resistant to osmotic and chemical (by n-butanol, saponin and sodium dodecyl sulfate (SDS)) hemolysis. Ultrasonic waves also have no effect upon these cells. Different behavior concerning the state of hemoglobin, K+ efflux, and swelling have also been observed, according to the pH of treatment. The results suggest that crosslinking involving hemoglobin molecules and components of the membrane (proteins, aminophospholipids) may be obtained in the reaction of human erythrocytes with glutaraldehyde.

Purification and Partial Characterization of a Lectin from Phaseolus vulgaris.

A method is presented for the isolation of a lectin from a Brazilian cultivar of the common bean (Phaseolus vulgaris L.), through extraction in acidic (pH 4.2) medium, fractionation with ammonium sulfate, and chromatography on DEAE-cellulose. The lectin was shown to be homogeneous by gel electrophoresis and isoelectric focusing.The molecular weight, determined by osmometry, is 100,250 daltons; the isoelectric point, determined by isoelectric focusing, is pH 5.1; and the extinction coefficient at 280 nm and pH 7 is E(1%) (1 cm) = 7.85.The lectin was shown to be a glycoprotein with 9.11% of neutral sugars and 1.44% of amino sugars. Its amino acid composition was characterized by the absence of methionine and a very low content of half-cystine, with a predominance of acidic and hydroxylated amino acids.The lectin presented no specificity when tested with red blood cells of all the groups of the ABO system.