Lectins are proteins found throughout nature that selectively bind to carbohydrates. They are classified based on their structure and specificity. Lectins serve many functions, including cell adhesion, glycoprotein synthesis, and defense against microorganisms. They play uncertain roles in plants but may be involved in germination and survival. Lectins can also recognize non-carbohydrate ligands and are used in medicine, research, and clinical applications like cell separation. Consuming large amounts of raw lectins from foods can cause digestive issues.

1. Presented By:
SyedaTamannaYasmin
1st semseter
M.Sc Microbiology
ID: DU2017MSC0130

2.  Lectins are a special class of proteins widely distributed in
nature, which selectively recognized and reversibly bind to
carbohydrates and glycoconjugates through their binding
sites.
 These are the proteins, which can be detected through
haemagglutination assays, interact with different
carbohydrates present in cell surfaces.
 Lectins are generally classified according to their structure,
specificity for carbohydrates and species location.
 Lectins are ubiquitous in nature and are found in many foods.
 Some foods such as beans and grains need to be cooked or
fermented to reduce lectins content, but the lectins
consumed in a typical balanced diet are not harmful.

5. • Lectins serve many different biological functions
in animals, from regulation of cell to adhesion
to glycoprotein synthesis and the control of
protein levels in the blood.
• They also may bind soluble extracellular and
intercellular glycoprotein.
• Some lectins are found on surface of mammalian
liver cells that specifically recognize galactose
residues.
• They help mediate the first-line defense against
invading microorganisms in animals.

6.  The function of lectins in plants is still uncertain. Once
thought to be necessary for rhizobia binding, this proposed
function was ruled out through lectin-
knockout transgene studies.
 The large concentration of lectins in plant seeds decreases
with growth, and suggests a role in plant germination and
perhaps in the seed's survival itself.
 The binding of glycoprotein on the surface of parasitic cells
also is believed to be a function.
 Several plant lectins have been found to recognize non-
carbohydrate ligands that are primarily hydrophobic in
nature. It has been suggested that these interactions may be
physiologically relevant, since some of these molecules
function as phytohormones.

7. • It is hypothesized that
some hepatitis C viral
glycoprotein attach to C-type
lectins on the host cell surface
(liver cells) for infection.

8.  Involved in various biological functions.
 They are used in medicine and medical
research.
 Use in studying of carbohydrates recognition by
protein.
 Use as biochemical tool
 Detection, isolation and identification of
complex carbohydrates.
 Also sometimes applied in clinical fields.
 Separation of cells.

9.  Ingesting lectins can cause
flatulence.
 Consuming legumes and grains in
their raw form can even result in
nausea, diarrhea and vomiting.