A pancreatic polypeptide of about 110 amino acids, depending on the species, that is the precursor of insulin. Proinsulin, produced by the PANCREATIC BETA CELLS, is comprised sequentially of the N-terminal B-chain, the proteolytically removable connecting C-peptide, and the C-terminal A-chain. It also contains three disulfide bonds, two between A-chain and B-chain. After cleavage at two locations, insulin and C-peptide are the secreted products. Intact proinsulin with low bioactivity also is secreted in small amounts.
The middle segment of proinsulin that is between the N-terminal B-chain and the C-terminal A-chain. It is a pancreatic peptide of about 31 residues, depending on the species. Upon proteolytic cleavage of proinsulin, equimolar INSULIN and C-peptide are released. C-peptide immunoassay has been used to assess pancreatic beta cell function in diabetic patients with circulating insulin antibodies or exogenous insulin. Half-life of C-peptide is 30 min, almost 8 times that of insulin.
A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).
Proprotein Convertase 2
Islets of Langerhans
Irregular microscopic structures consisting of cords of endocrine cells that are scattered throughout the PANCREAS among the exocrine acini. Each islet is surrounded by connective tissue fibers and penetrated by a network of capillaries. There are four major cell types. The most abundant beta cells (50-80%) secrete INSULIN. Alpha cells (5-20%) secrete GLUCAGON. PP cells (10-35%) secrete PANCREATIC POLYPEPTIDE. Delta cells (~5%) secrete SOMATOSTATIN.
Proprotein Convertase 1
Antibodies specific to INSULIN.
Proteolytic enzymes that are involved in the conversion of protein precursors such as peptide prohormones into PEPTIDE HORMONES. Some are ENDOPEPTIDASES, some are EXOPEPTIDASES.
A type of pancreatic cell representing about 50-80% of the islet cells. Beta cells secrete INSULIN.
Diabetes Mellitus, Type 1
A subtype of DIABETES MELLITUS that is characterized by INSULIN deficiency. It is manifested by the sudden onset of severe HYPERGLYCEMIA, rapid progression to DIABETIC KETOACIDOSIS, and DEATH unless treated with insulin. The disease may occur at any age, but is most common in childhood or adolescence.
Protein Processing, Post-Translational
Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.
An oily liquid extracted from the seeds of the safflower, Carthamus tinctorius. It is used as a dietary supplement in the management of HYPERCHOLESTEROLEMIA. It is used also in cooking, as a salad oil, and as a vehicle for medicines, paints, varnishes, etc. (Dorland, 28th ed & Random House Unabridged Dictionary, 2d ed)
A plant genus of the family ASTERACEAE. Oil from the seed (SAFFLOWER OIL) is an important food oil of commerce.
An individual's objective and insightful awareness of the feelings and behavior of another person. It should be distinguished from sympathy, which is usually nonobjective and noncritical. It includes caring, which is the demonstration of an awareness of and a concern for the good of others. (From Bioethics Thesaurus, 1992)
An autosomal recessive neurodegenerative disorder caused by the absence or deficiency of BETA-GALACTOSIDASE. It is characterized by intralysosomal accumulation of G(M1) GANGLIOSIDE and oligosaccharides, primarily in neurons of the central nervous system. The infantile form is characterized by MUSCLE HYPOTONIA, poor psychomotor development, HIRSUTISM, hepatosplenomegaly, and facial abnormalities. The juvenile form features HYPERACUSIS; SEIZURES; and psychomotor retardation. The adult form features progressive DEMENTIA; ATAXIA; and MUSCLE SPASTICITY. (From Menkes, Textbook of Child Neurology, 5th ed, pp96-7)
The property of antibodies which enables them to react with some ANTIGENIC DETERMINANTS and not with others. Specificity is dependent on chemical composition, physical forces, and molecular structure at the binding site.
A cell surface receptor for INSULIN. It comprises a tetramer of two alpha and two beta subunits which are derived from cleavage of a single precursor protein. The receptor contains an intrinsic TYROSINE KINASE domain that is located within the beta subunit. Activation of the receptor by INSULIN results in numerous metabolic changes including increased uptake of GLUCOSE into the liver, muscle, and ADIPOSE TISSUE.
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.
A lysosomal cysteine proteinase with a specificity similar to that of PAPAIN. The enzyme is present in a variety of tissues and is important in many physiological and pathological processes. In pathology, cathepsin B has been found to be involved in DEMYELINATION; EMPHYSEMA; RHEUMATOID ARTHRITIS, and NEOPLASM INVASIVENESS.
The normal lack of the ability to produce an immunological response to autologous (self) antigens. A breakdown of self tolerance leads to autoimmune diseases. The ability to recognize the difference between self and non-self is the prime function of the immune system.
Adenoma, Islet Cell
A benign tumor of the pancreatic ISLET CELLS. Usually it involves the INSULIN-producing PANCREATIC BETA CELLS, as in INSULINOMA, resulting in HYPERINSULINISM.