Glycoside hydrolase family 56
Encyclopedia
In molecular biology, glycoside hydrolase family 56 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. 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 56 CAZY GH_56 includes enzymes with hyaluronidase
activity. The venom of Apis mellifera (Honeybee) contains several biologically-active peptides and two enzymes, one of which is a hyaluronidase. The amino acid sequence of bee venom hyaluronidase contains 349 amino acids, and includes four cysteines and a number of potential glycosylation sites. The sequence shows a high degree of similarity to PH-20, a membrane protein
of mammalian sperm
involved in sperm-egg adhesion, supporting the view that hyaluronidases play a role in fertilisation
.
PH-20 is required for sperm adhesion to the egg zona pellucida
; it is located on both the sperm plasma membrane and acrosomal membrane. The amino acid sequence of the mature protein contains 468 amino acids, and includes six potential N-linked glycosylation
sites and twelve cysteines
, eight of which are tightly clustered near the C-terminus.
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 56 CAZY GH_56 includes enzymes with hyaluronidase
Hyaluronidase
The hyaluronidases are a family of enzymes that degrade hyaluronic acid.In humans, there are six associated genes, including HYAL1, HYAL2, HYAL3, and PH-20/SPAM1.-Use as a drug:...
activity. The venom of Apis mellifera (Honeybee) contains several biologically-active peptides and two enzymes, one of which is a hyaluronidase. The amino acid sequence of bee venom hyaluronidase contains 349 amino acids, and includes four cysteines and a number of potential glycosylation sites. The sequence shows a high degree of similarity to PH-20, a membrane protein
Membrane protein
A membrane protein is a protein molecule that is attached to, or associated with the membrane of a cell or an organelle. More than half of all proteins interact with membranes.-Function:...
of mammalian sperm
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
involved in sperm-egg adhesion, supporting the view that hyaluronidases play a role in fertilisation
Fertilisation
Fertilisation is the fusion of gametes to produce a new organism. In animals, the process involves the fusion of an ovum with a sperm, which eventually leads to the development of an embryo...
.
PH-20 is required for sperm adhesion to the egg zona pellucida
Zona pellucida
The zona pellucida is a glycoprotein membrane surrounding the plasma membrane of an oocyte. It is a vital constitutive part of the latter, external but of essential importance to it...
; it is located on both the sperm plasma membrane and acrosomal membrane. The amino acid sequence of the mature protein contains 468 amino acids, and includes six potential N-linked glycosylation
Glycosylation
Glycosylation is the reaction in which a carbohydrate, i.e. a glycosyl donor, is attached to a hydroxyl or other functional group of another molecule . In biology glycosylation refers to the enzymatic process that attaches glycans to proteins, lipids, or other organic molecules...
sites and twelve cysteines
Cysteine
Cysteine is an α-amino acid with the chemical formula HO2CCHCH2SH. It is a non-essential amino acid, which means that it is biosynthesized in humans. Its codons are UGU and UGC. The side chain on cysteine is thiol, which is polar and thus cysteine is usually classified as a hydrophilic amino acid...
, eight of which are tightly clustered near the C-terminus.