Sucrose alpha-glucosidase (, ''sucrose alpha-glucohydrolase'', ''
sucrase Sucrase is a digestive enzyme that catalyzes the hydrolysis of sucrose to its subunits fructose and glucose. One form, sucrase-isomaltase, is secreted in the small intestine on the brush border. The sucrase enzyme invertase, which occurs more com ...
'', ''sucrase-isomaltase'', ''sucrose.alpha.-glucohydrolase'', ''intestinal sucrase'', ''sucrase(invertase)'') is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
with
systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature.
A semisystematic name or semitrivial ...
''sucrose-alpha-D-glucohydrolase''.
This enzyme
catalyses the following
chemical reaction
A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and break ...
:
Hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile.
Biological hydrolysis ...
of
sucrose
Sucrose, a disaccharide, is a sugar composed of glucose and fructose subunits. It is produced naturally in plants and is the main constituent of white sugar. It has the molecular formula .
For human consumption, sucrose is extracted and refi ...
and
maltose
}
Maltose ( or ), also known as maltobiose or malt sugar, is a disaccharide formed from two units of glucose joined with an α(1→4) bond. In the isomer isomaltose, the two glucose molecules are joined with an α(1→6) bond. Maltose is the tw ...
by an alpha-D-glucosidase-type action
This enzyme is isolated from
intestinal mucosa
The gastrointestinal wall of the gastrointestinal tract is made up of four layers of specialised tissue. From the inner cavity of the gut (the lumen) outwards, these are:
# Mucosa
# Submucosa
# Muscular layer
# Serosa or adventitia
The mucos ...
as a single
polypeptide
Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides ...
chain. The human
sucrase-isomaltase
Oligo-1,6-glucosidase (EC 3.2.1.10, sucrase-isomaltase, SI; systematic name oligosaccharide 6-α-glucohydrolase) is a glucosidase enzyme located on the brush border of the small intestine, which catalyses the following reaction:
:Hydrolysis of ( ...
is a dual-function enzyme with two GH31 domains, one serving as the
isomaltase
Isomaltase () is an enzyme that breaks the bonds linking saccharides, which cannot be broken by amylase or maltase. It digests polysaccharides at the alpha 1-6 linkages. Its substrate, alpha-limit dextrin, is a product of amylopectin digestion t ...
, the other serving as a sucrose alpha-glucosidase.
References
External links
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EC 3.2.1