Peanut agglutinin binds preferentially to the T-antigen, a galactosyl
(β-1,3) N-acetylgalactosamine structure present in many
glycoconjugates such as M and N blood groups, gangliosides,
and many other soluble and membrane-associated
glycoproteins and glycolipids. With certain exceptions, the
receptor sequence for PNA is normally sialylated which
prevents the lectin from binding to its receptor oligosaccharide
(see Jacalin). Even sialic acid which is not bound directly to the
receptor sugars may inhibit binding. The presence of calcium
ions in diluents can enhance the binding of PNA to receptors,
possibly by neutralizing the negative charges on sialic acid
residues adjacent to the receptor sequence.
PNA is useful in distinguishing between normal and tumor
tissues and in assessing malignancy in transitional mucosa. In
addition, PNA binding can be used to measure cellular maturity
in lymphoid tissues, to distinguish a variety of lymphocyte
subpopulations in man and experimental animals, and to
measure the levels of lymphoid cell populations in many
diseases. PNA can be employed in the fractionation of stem
cells in mice for use in bone marrow transplantation across
histocompatibility barriers.
A major cell surface receptor for PNA may be asialo GM1
ganglioside. Since PNA shares specificity with the antibody
to this glycolipid, PNA and the antibody can be used
interchangeably in some applications.
Inhibiting/Eluting Sugar: 200 mM galactose
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Sheep trachea: Peanut agglutinin (brown, DAB).
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