Peanut agglutinin is plant lectin

Lectin

Lectins are sugar-binding proteins that are highly specific for their sugar moieties. They play a role in biological recognition phenomena involving cells and proteins. For example, some viruses use lectins to attach themselves to the cells of the host organism during infection...

 protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 derived from the fruit

Fruit

In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...

s of Arachis hypogaea. Peanut agglutinin may also be referred to as Arachis hypogaea lectin. Lectins recognise and bind particular sugar

Sugar

Sugar is a class of edible crystalline carbohydrates, mainly sucrose, lactose, and fructose, characterized by a sweet flavor.Sucrose in its refined form primarily comes from sugar cane and sugar beet...

 sequences in carbohydrates; peanut agglutinin binds the carbohydrate sequence Gal

Galactose

Galactose , sometimes abbreviated Gal, is a type of sugar that is less sweet than glucose. It is a C-4 epimer of glucose....

-β(1-3)-GalNAc

N-Acetylgalactosamine

N-Acetylgalactosamine , is an amino sugar derivative of galactose.-Function:In humans it is the terminal carbohydrate forming the antigen of blood group A....

. The name "peanut agglutinin" originates from its ability to stick together (agglutinate) cells, such as neuramidase-treated erythrocytes, which have glycoprotein

Glycoprotein

Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...

s or glycolipid

Glycolipid

Glycolipids are lipids with a carbohydrate attached. Their role is to provide energy and also serve as markers for cellular recognition.-Metabolism:...

s on their surface which include the Gal-β(1-3)-GalNAc carbohydrate sequence.

Uses in cell biology and biochemistry

Because peanut agglutinin specifically binds a particular carbohydrate sequence it finds use in a range of methods for cell biology

Cell biology

Cell biology is a scientific discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level...

 and biochemistry

Biochemistry

Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...

. For example in PNA-affinity chromatography

Affinity chromatography

Affinity chromatography is a method of separating biochemical mixtures and based on a highly specific interaction such as that between antigen and antibody, enzyme and substrate, or receptor and ligand.-Uses:Affinity chromatography can be used to:...

 the binding specificity of peanut agglutinin is used to isolate glycosylated molecules which have the sugar sequence Gal-β(1-3)-GalNAc. Peanut agglutinin activity is inhibited by lactose

Lactose

Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from or , the Latin word for milk,...

 and galactose

Galactose

Galactose , sometimes abbreviated Gal, is a type of sugar that is less sweet than glucose. It is a C-4 epimer of glucose....

 which compete for the binding site.

Other uses include:

• Potent anti-T cell
  T cell
  T cells or T lymphocytes belong to a group of white blood cells known as lymphocytes, and play a central role in cell-mediated immunity. They can be distinguished from other lymphocytes, such as B cells and natural killer cells , by the presence of a T cell receptor on the cell surface. They are...
  
   activity.
• Distinguishing between human lymphocyte
  Lymphocyte
  A lymphocyte is a type of white blood cell in the vertebrate immune system.Under the microscope, lymphocytes can be divided into large lymphocytes and small lymphocytes. Large granular lymphocytes include natural killer cells...
  
   subsets.
• Tumour tissue
  Tissue (biology)
  Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...
  
   determination for transitional mucosa malignancies.
• Identification of mammalian-infective metacyclic promastigote Leishmania major
  Leishmania major
  Leishmania major is a species of Leishmania.It is associated with zoonotic cutaneous leishmaniasis.The genome has been sequenced....
  
   parasites from other life cycle forms also found in the sandfly
  Sandfly
  thumb|Sandfly biting a human's little fingerthumb|Sandfly biteSandfly is a colloquial name for any species or genus of flying, biting, blood-sucking Dipteran encountered in sandy areas...
  
  host.