Endorphins are peptides produced in the brain that block the perception of pain and increase feelings of wellbeing. They are produced and stored in the pituitary gland of the brain. Endorphins are endogenous painkillers often produced in the brain and adrenal medulla during physical exercise or orgasm and inhibit pain, muscle cramps, and relieve stress.
Pro-opiomelanocortin (POMC) is a precursor polypeptide with 241 amino acid residues. POMC is synthesized in corticotrophs of the anterior pituitary from the 267-amino-acid-long polypeptide precursor pre-pro-opiomelanocortin (pre-POMC), by the removal of a 26-amino-acid-long signal peptide sequence during translation. POMC is part of the central melanocortin system.
Leptin is a protein hormone predominantly made by adipocytes and its primary role is likely to regulate long-term energy balance.
Neuropeptide Y (NPY) is a 36 amino-acid neuropeptide that is involved in various physiological and homeostatic processes in both the central and peripheral nervous systems. It is secreted alongside other neurotransmitters such as GABA and glutamate.
An enkephalin is a pentapeptide involved in regulating nociception in the body. The enkephalins are termed endogenous ligands, as they are internally derived and bind to the body's opioid receptors. Discovered in 1975, two forms of enkephalin have been found, one containing leucine ("leu"), and the other containing methionine ("met"). Both are products of the proenkephalin gene.
β-Endorphin (beta-endorphin) is an endogenous opioid neuropeptide and peptide hormone that is produced in certain neurons within the central nervous system and peripheral nervous system. It is one of three endorphins that are produced in humans, the others of which include α-endorphin and γ-endorphin.
Amylin, or islet amyloid polypeptide (IAPP), is a 37-residue peptide hormone. It is co-secreted with insulin from the pancreatic β-cells in the ratio of approximately 100:1 (insulin:amylin). Amylin plays a role in glycemic regulation by slowing gastric emptying and promoting satiety, thereby preventing post-prandial spikes in blood glucose levels.
Agouti-related protein (AgRP), also called agouti-related peptide, is a neuropeptide produced in the brain by the AgRP/NPY neuron. It is synthesized in neuropeptide Y (NPY)-containing cell bodies located in the ventromedial part of the arcuate nucleus in the hypothalamus. AgRP is co-expressed with NPY and acts to increase appetite and decrease metabolism and energy expenditure. It is one of the most potent and long-lasting of appetite stimulators. In humans, the agouti-related peptide is encoded by the AGRP gene.
Proprotein convertase 1, also known as prohormone convertase, prohormone convertase 3, or neuroendocrine convertase 1 and often abbreviated as PC1/3 is an enzyme that in humans is encoded by the PCSK1 gene. PCSK1 and PCSK2 differentially cleave proopiomelanocortin and they act together to process proinsulin and proglucagon in pancreatic islets.
Agouti-signaling protein is a protein that in humans is encoded by the ASIP gene. It is responsible for the distribution of melanin pigment in mammals. Agouti interacts with the melanocortin 1 receptor to determine whether the melanocyte produces phaeomelanin, or eumelanin. This interaction is responsible for making distinct light and dark bands in the hairs of animals such as the agouti, which the gene is named after. In other species such as horses, agouti signalling is responsible for determining which parts of the body will be red or black. Mice with wildtype agouti will be grey-brown, with each hair being partly yellow and partly black. Loss of function mutations in mice and other species cause black fur coloration, while mutations causing expression throughout the whole body in mice cause yellow fur and obesity.
Proprotein convertases (PPCs) are a family of proteins that activate other proteins. Many proteins are inactive when they are first synthesized, because they contain chains of amino acids that block their activity. Proprotein convertases remove those chains and activate the protein. The prototypical proprotein convertase is furin. Proprotein convertases have medical significance, because they are involved in many important biological processes, such as cholesterol synthesis. Compounds called proprotein convertase inhibitors can block their action, and block the target proteins from becoming active. Many proprotein convertases, especially furin and PACE4, are involved in pathological processes such as viral infection, inflammation, hypercholesterolemia, and cancer, and have been postulated as therapeutic targets for some of these diseases.
Proprotein convertase 2 (PC2) also known as prohormone convertase 2 or neuroendocrine convertase 2 (NEC2) is a serine protease and proprotein convertase PC2, like proprotein convertase 1 (PC1), is an enzyme responsible for the first step in the maturation of many neuroendocrine peptides from their precursors, such as the conversion of proinsulin to insulin intermediates. To generate the bioactive form of insulin, a second step involving the removal of C-terminal basic residues is required; this step is mediated by carboxypeptidases E and/or D. PC2 plays only a minor role in the first step of insulin biosynthesis, but a greater role in the first step of glucagon biosynthesis compared to PC1. PC2 binds to the neuroendocrine protein named 7B2, and if this protein is not present, proPC2 cannot become enzymatically active. 7B2 accomplishes this by preventing the aggregation of proPC2 to inactivatable forms. The C-terminal domain of 7B2 also inhibits PC2 activity until it is cleaved into smaller inactive forms that lack carboxy-terminal basic residues. Thus, 7B2 is both an activator and an inhibitor of PC2. PC2 has been identified in a number of animals, including C. elegans.
Peptide YY (PYY) also known as peptide tyrosine tyrosine is a peptide that in humans is encoded by the PYY gene. Peptide YY is a short peptide released from cells in the ileum and colon in response to feeding. In the blood, gut, and other elements of periphery, PYY acts to reduce appetite; similarly, when injected directly into the central nervous system, PYY is also anorexigenic, i.e., it reduces appetite.
Met-enkephalin, also known as metenkefalin (INN), sometimes referred to as opioid growth factor (OGF), is a naturally occurring, endogenous opioid peptide that has opioid effects of a relatively short duration. It is one of the two forms of enkephalin, the other being leu-enkephalin. The enkephalins are considered to be the primary endogenous ligands of the δ-opioid receptor, due to their high potency and selectivity for the site over the other endogenous opioids.
Carboxypeptidase Z is an enzyme that in humans is encoded by the CPZ gene.
An Oligopeptidase is an enzyme that cleaves peptides but not proteins. This property is due to its structure: the active site of this enzyme is located at the end of a narrow cavity which can only be reached by peptides.
Carboxypeptidase A6 (CPA6) is a metallocarboxypeptidase enzyme that in humans is encoded by the CPA6 gene. It is highly expressed in the adult mouse olfactory bulb and is broadly expressed in the embryonic brain and other tissues.
Carboxypeptidase M is an enzyme. This enzyme catalyses the following chemical reaction
Carboxypeptidase D can refer to one of several enzymes. A family of serine carboxypeptidases includes is an enzyme. This enzyme has an optimal pH of 4.5-6.0, is inhibited by diisopropyl fluorophosphate, and catalyses the following chemical reaction
AE binding protein 1 is a protein that in humans is encoded by the AEBP1 gene.
