In molecular biology, the carboxypeptidase A inhibitor family is a family of proteins which is represented by the well-characterised

metallocarboxypeptidase A metalloexopeptidase is a type of enzyme that acts as a metalloproteinase exopeptidase. These enzymes have a catalytic mechanism involving a metal, often zinc. They function in molecular biology as agents that cut the terminal (or penultimate) p ...

A inhibitor (MCPI) from potatoes, which belongs to the MEROPS inhibitor family I37, clan IE. It inhibits metallopeptidases belonging to MEROPS peptidase family M14,

carboxypeptidase A Carboxypeptidase A usually refers to the pancreatic exopeptidase that hydrolyzes peptide bonds of C-terminal residues with aromatic or aliphatic side-chains. Most scientists in the field now refer to this enzyme as CPA1, and to a related pancrea ...

. In

Russet Burbank Russet Burbank is a potato cultivar with dark brown skin and few eyes that is the most widely grown potato in North America. A russet type, its flesh is white, dry, and mealy, and it is good for baking, mashing, and french fries (chips). It i ...

potatoes, it is a mixture of approximately equal amounts of two

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. A p ...

chains containing 38 or 39

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

residues. The chains differ in their

amino terminal The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the ami ...

sequence only and are resistant to fragmentation by

protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalyzes (increases reaction rate or "speeds up") proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the ...

s. The

structure A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...

of the

complex Complex commonly refers to: * Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe ** Complex system, a system composed of many components which may interact with each ...

between

bovine Bovines (subfamily Bovinae) comprise a diverse group of 10 genera of medium to large-sized ungulates, including cattle, bison, African buffalo, water buffalos, and the four-horned and spiral-horned antelopes. The evolutionary relationship betwee ...

carboxypeptidase A and the 39-amino-acid carboxypeptidase A inhibitor from potatoes has been determined at 2.5-

Angstrom The angstromEntry "angstrom" in the Oxford online dictionary. Retrieved on 2019-03-02 from https://en.oxforddictionaries.com/definition/angstrom.Entry "angstrom" in the Merriam-Webster online dictionary. Retrieved on 2019-03-02 from https://www.m ...

resolution. The

potato The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae. Wild potato species can be found from the southern Unit ...

inhibitor is synthesised as a precursor, having a 29 amino acid N-terminal signal peptide, a 27 amino acid pro-peptide, the 39 amino acid mature inhibitor region and a 7 amino acid C-terminal extension. The 7 amino acid C-terminal extension is involved in inhibitor inactivation and may be required for targeting to the

vacuole A vacuole () is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal, and bacterial cells. Vacuoles are essentially enclosed compartments which are filled with water containing inorganic and organic mo ...

where the mature active inhibitor accumulates. The N-terminal region and the mature inhibitor are weakly related to other solananaceous

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

s found in this family, from potato, tomato and henbane, which have been incorrectly described as

inhibitors.

References

External links

MEROPS inhibitor family I37

MEROPS peptidase family M14
{{InterPro content, IPR004231 Protein domains