Role of muscle endopeptidases
and their inhibitors in meat tenderness.
In their resting saliva, sensitive subjects had higher amounts of endopeptidases
, enzymes that cut up proteins, than non-sensitive subjects.
Beside its classical role as the major regulator for calcium absorption, vitamin D mediates the activity of [beta]-cell calcium-dependent endopeptidases
, promotes conversion of proinsulin to insulin and increases insulin output.
They belong to the family of endopeptidases
that break down elements of the extracellular matrix, resulting in its continuous remodeling.
Proteinases or endopeptidases
are protease enzymes that hydrolyze internal peptide bonds in a protein.
It is composed of endopeptidases
(ananain, comosain), phosphatases, glucosidases, peroxidases, escharase, cellulases, glycoproteins, proteinase inhibitors (cystatin), calcium and carbohydrate.
NEP belongs to the M13 subfamily of neutral endopeptidases
and consists of a short intracellular N-terminal domain, a single transmembrane helix, and a large C-terminal extracellular domain (3).
It is generally accepted that endopeptidases
like trypsin (Try) or chymotrypsin (Chy) initiate the hydrolysis of protein-releasing polypeptides that are further hydrolyzed by other endopeptidases
yielding smaller polypeptides available for exopeptidases; Try hydrolyzes the peptide bond formed by the carboxylic side of lysine or arginine, whereas Chy at voluminous hydrophobic amino acids like tyrosine, tryptophan, or phenylalanine.
The latex from unripe papaya fruit contains enzymes papain and chymopapain; other components include a mixture of cysteine endopeptidases
, chitinases, and an inhibitor of serine protease.
Although bradykinin is degraded by other peptidases--for example, aminopeptidases M, carboxypeptidases N, neutral endopeptidases
, dipeptidyl peptidase IV, enkephalinases, or neprilysin--these enzymes are less effective than ACE (7).
There are different type of cysteine endopeptidases
such as papain, chymopapain, glycol endopeptidases
, in the degradation of extracellular matrix components during tumor invasion and metastasis as well as their role in the processes of tissue destruction and remodeling during inflammation have been proposed.