Serpins
A family of serine proteinase inhibitors which are similar in amino acid sequence and mechanism of inhibition, but differ in their specificity toward proteolytic enzymes. This family includes alpha 1-antitrypsin, angiotensinogen, ovalbumin, antiplasmin, alpha 1-antichymotrypsin, thyroxine-binding protein, complement 1 inactivators, antithrombin III, heparin cofactor II, plasminogen inactivators, gene Y protein, placental plasminogen activator inhibitor, and barley Z protein. Some members of the serpin family may be substrates rather than inhibitors of SERINE ENDOPEPTIDASES, and some serpins occur in plants where their function is not known.
Serine Proteinase Inhibitors
Exogenous or endogenous compounds which inhibit SERINE ENDOPEPTIDASES.
alpha 1-Antitrypsin
alpha 1-Antichymotrypsin
Glycoprotein found in alpha(1)-globulin region in human serum. It inhibits chymotrypsin-like proteinases in vivo and has cytotoxic killer-cell activity in vitro. The protein also has a role as an acute-phase protein and is active in the control of immunologic and inflammatory processes, and as a tumor marker. It is a member of the serpin superfamily.
Genes, Tumor Suppressor
Leukocyte Elastase
An enzyme that catalyzes the hydrolysis of proteins, including elastin. It cleaves preferentially bonds at the carboxyl side of Ala and Val, with greater specificity for Ala. EC 3.4.21.37.
Protein C Inhibitor
A member of the serpin family of proteins that is found in plasma and urine. It is dependent on heparin and is able to inhibit activated PROTEIN C; THROMBIN; KALLIKREIN; and other SERINE ENDOPEPTIDASES.
Complement C1 Inactivator Proteins
Serum proteins that inhibit, antagonize, or inactivate COMPLEMENT C1 or its subunits.
Protease Nexins
Extracellular protease inhibitors that are secreted from FIBROBLASTS. They form a covalent complex with SERINE PROTEASES and can mediate their cellular internalization and degradation.
Molecular Sequence Data
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Amino Acid Sequence
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Serine Endopeptidases
Pancreatic Elastase
A protease of broad specificity, obtained from dried pancreas. Molecular weight is approximately 25,000. The enzyme breaks down elastin, the specific protein of elastic fibers, and digests other proteins such as fibrin, hemoglobin, and albumin. EC 3.4.21.36.
Antithrombins
Endogenous factors and drugs that directly inhibit the action of THROMBIN, usually by blocking its enzymatic activity. They are distinguished from INDIRECT THROMBIN INHIBITORS, such as HEPARIN, which act by enhancing the inhibitory effects of antithrombins.
Serpin E2
Cathepsin G
A serine protease found in the azurophil granules of NEUTROPHILS. It has an enzyme specificity similar to that of chymotrypsin C.
alpha-2-Antiplasmin
A member of the serpin superfamily found in plasma that inhibits the lysis of fibrin clots which are induced by plasminogen activator. It is a glycoprotein, molecular weight approximately 70,000 that migrates in the alpha 2 region in immunoelectrophoresis. It is the principal plasmin inactivator in blood, rapidly forming a very stable complex with plasmin.
Cowpox virus
Plasminogen Activator Inhibitor 1
A member of the serpin family of proteins. It inhibits both the tissue-type and urokinase-type plasminogen activators.
Protein Conformation
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Antithrombin III
Prolamins
A group of seed storage proteins restricted to the POACEAE family. They are rich in GLUTAMINE and PROLINE.
Proteins
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
Cystatin A
A cytastin subtype found at high levels in the SKIN and in BLOOD CELLS. Cystatin A incorporates into the cornified cell envelope of stratified squamous epithelial cells and may play a role in bacteriostatic properties of skin.
Heparin Cofactor II
A sulfated plasma protein with a MW of approximately 66kDa that resembles ANTITHROMBIN III. The protein is an inhibitor of thrombin in plasma and is activated by dermatan sulfate or heparin. It is a member of the serpin superfamily.
Chymotrypsin
Models, Molecular
Trypsin Inhibitors
Brenner Tumor
A smooth, solid or cystic fibroepithelial (FIBROEPITHELIAL NEOPLASMS) tumor, usually found in the OVARIES but can also be found in the adnexal region and the KIDNEYS. It consists of a fibrous stroma with nests of epithelial cells that sometimes resemble the transitional cells lining the urinary bladder. Brenner tumors generally are benign and asymptomatic. Malignant Brenner tumors have been reported.
Granzymes
A family of serine endopeptidases found in the SECRETORY GRANULES of LEUKOCYTES such as CYTOTOXIC T-LYMPHOCYTES and NATURAL KILLER CELLS. When secreted into the intercellular space granzymes act to eliminate transformed and virus-infected host cells.
Plasminogen Activator Inhibitor 2
Member of the serpin family of proteins. It inhibits both the tissue-type and urokinase-type plasminogen activators.
Sequence Alignment
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
Protein Binding
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Catechol Oxidase
An enzyme of the oxidoreductase class that catalyzes the reaction between catechol and oxygen to yield benzoquinone and water. It is a complex of copper-containing proteins that acts also on a variety of substituted catechols. EC 1.10.3.1.
Protease Inhibitors
Cathepsins
A group of lysosomal proteinases or endopeptidases found in aqueous extracts of a variety of animal tissues. They function optimally within an acidic pH range. The cathepsins occur as a variety of enzyme subtypes including SERINE PROTEASES; ASPARTIC PROTEINASES; and CYSTEINE PROTEASES.
Sequence Homology, Amino Acid
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Cucurbita
Urokinase-Type Plasminogen Activator
Binding Sites
Electrophoresis, Polyacrylamide Gel
Protein Structure, Secondary
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.