The nature of lectins from Dolichos lablab.
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Date
1986-03
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Abstract
The lectins from the seeds of Dolichos lablab var. lignosus (field bean) and Dolichos
lablab var. typicus (lablab bean) have been isolated in a homogeneous form by affinity
chromatography on D-mannose linked Sepharose. Both the lectins are glycoproteins and have
a molecular weight of 60,000 and S 20,w value of 5·2 and seem to be made up of 4 similar
subunits (apparent molecular weight 15,000). The carbohydrate content ofthe lectins is mostly
fucose (2-5 mol per mol of protein), mannose (5-8 mol per mol of protein) and N-acetyl
glucosamine (1–2 mol per mol of protein). The amino acid composition of both the lectins was
similar and methionine and half cystine could not be detected, Both the lectins have similar
tryptic peptide map. Alanine and serine were the only Ν and C-terminal amino acids for both
lectins. The lectins were found to contain low amounts of bound metals such as manganese,
magnesium and calcium. The near ultra-violet circular dichroism spectra of the lectins are
similar to that of Sainfoin. Circular dichroism data indicate that tyrosine and tryptophan
residues are involved in sugar binding.
The lectins are nonspecific for human blood groups and they agglutinate a variety of other
erythrocytes. Among a number of sugars, D-glucose and D-mannose inhibited the haemagglutinating
activity of the lectins. The lectins were antigenically similar.
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Keywords
Dolichos lablab, lectin, field bean, lablab bean, physicochemical and biological properties
Citation
Kumar N Siva, Rao D Rajagopal. The nature of lectins from Dolichos lablab. Journal of Biosciences. 1986 Mar; 10(1): 95-109.