Glycoside hydrolase family 36
Encyclopedia
In molecular biology, glycoside hydrolase family 36 is a family
Protein family
A protein family is a group of evolutionarily-related proteins, and is often nearly synonymous with gene family. The term protein family should not be confused with family as it is used in taxonomy....

 of glycoside hydrolases
Glycoside hydrolase
Glycoside hydrolases catalyze the hydrolysis of the glycosidic linkage to release smaller sugars...

.

Glycoside hydrolases  are a widespread group of enzymes that hydrolyse the glycosidic bond
Glycosidic bond
In chemistry, a glycosidic bond is a type of covalent bond that joins a carbohydrate molecule to another group, which may or may not be another carbohydrate....

 between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety. A classification system for glycoside hydrolases, based on sequence similarity, has led to the definition of >100 different families. This classification is available on the CAZy(http://www.cazy.org/GH1.html) web site, and also discussed at CAZypedia, an online encyclopedia of carbohydrate active enzymes.

Glycoside hydrolase family 36 together with family 31
Glycoside hydrolase family 31
In molecular biology, glycoside hydrolase family 31 is a family of glycoside hydrolases.Glycoside hydrolases are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety...

 and family 27
Glycoside hydrolase family 27
In molecular biology, glycoside hydrolase family 27 is a family of glycoside hydrolases.Glycoside hydrolases are a widespread group of enzymes that hydrolyse the glycosidic bond between two or more carbohydrates, or between a carbohydrate and a non-carbohydrate moiety...

 alpha-galactosidases
Alpha-galactosidase
Alpha-galactosidase is a glycoside hydrolase enzyme that hydrolyses the terminal alpha-galactosyl moieties from glycolipids and glycoproteins. It is encoded by the gene.- Function :...

 form the glycosyl hydrolase clan GH-D (CAZY GH), a superfamily of alpha-galactosidases, alpha-N-acetylgalactosaminidases, and isomaltodextranases which are likely to share a common catalytic mechanism and structural topology.

Alpha-galactosidase (melibiase) catalyzes the hydrolysis of melibiose
Melibiose
Melibiose is a reducing disaccharide formed by an alpha-1,6 linkage between galactose and glucose . It can be formed by invertase mediated hydrolysis of raffinose, which produces melibiose and fructose. Melibiose can be broken down into its component saccharides, glucose and galactose, by the...

 into 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....

 and glucose
Glucose
Glucose is a simple sugar and an important carbohydrate in biology. Cells use it as the primary source of energy and a metabolic intermediate...

. In man, the deficiency of this enzyme is the cause of Fabry's disease
Fabry's disease
Fabry disease is a rare X-linked recessive lysosomal storage disease, which can cause a wide range of systemic symptoms...

 (X-linked sphingolipidosis). Alpha-galactosidase is present in a variety of organisms. There is a considerable degree of similarity in the sequence of alpha-galactosidase from various eukaryotic species. Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...

alpha-galactosidase (gene melA), which requires NAD and magnesium as cofactors, is not structurally related to the eukaryotic enzymes; by contrast, an Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...

plasmid
Plasmid
In microbiology and genetics, a plasmid is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA. They are double-stranded and, in many cases, circular...

 encoded alpha-galactosidase (gene rafA ) contains a region of about 50 amino acids which is similar to a domain of the eukaryotic alpha-galactosidases. Alpha-N-acetylgalactosaminidase catalyzes the hydrolysis of terminal non-reducing N-acetyl-D-galactosamine residues in N-acetyl-alpha-D- galactosaminides. In man, the deficiency of this enzyme is the cause of Schindler
Schindler disease
Schindler disease, also known as Kanzaki disease and Alpha-N-acetylgalactosaminidase deficiency is a rare congenital metabolic disorder in humans...

 and Kanzaki diseases. The sequence of this enzyme is highly related to that of the eukaryotic alpha-galactosidases.

This family also icludes raffinose
Raffinose
Raffinose is a trisaccharide composed of galactose, fructose, and glucose. It can be found in beans, cabbage, brussels sprouts, broccoli, asparagus, other vegetables, and whole grains. Raffinose can be hydrolyzed to D-galactose and sucrose by the enzyme α-galactosidase , an enzyme not found in the...

 synthase proteins, also known as seed inhibition (Sip1) 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...

s. Raffinose (O-alpha- D-galactopyranosyl- (1-->6)- O-alpha- D-glucopyranosyl-(1<-->2)- O-beta- D-fructofuranoside) is a widespread oligosaccharide
Oligosaccharide
An oligosaccharide is a saccharide polymer containing a small number of component sugars, also known as simple sugars...

 in plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

 seeds
SEEDS
SEEDS is a voluntary organisation registered under the Societies Act of India....

 and other 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...

s. Raffinose synthase is the key enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 that channels sucrose
Sucrose
Sucrose is the organic compound commonly known as table sugar and sometimes called saccharose. A white, odorless, crystalline powder with a sweet taste, it is best known for its role in human nutrition. The molecule is a disaccharide composed of glucose and fructose with the molecular formula...

into the raffinose oligosaccharide pathway.

Glycoside hydrolase family 36 also includes enzymes with α-N-acetylgalactosaminidase and stachyose synthase activities.

Glycoside hydrolase family 36 can be subdivided into 11 families, GH36A to GH36K.
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