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An alpha helix is a sequence of amino acids in a protein that are twisted into a coil.
Colostrum is the first form of milk produced by the mammary glands of humans and other mammals immediately following delivery of the newborn. It may be called beestings, the traditional word from Old English dialects, when referring to the first milk of a cow or other animals. Most species will begin to generate colostrum just prior to giving birth. Colostrum has an especially high amount of bioactive compounds compared to mature milk to give the newborn the best possible start to life. Specifically, colostrum contains antibodies to protect the newborn against disease and infection, and immune and growth factors and other bioactives that help to activate a newborn's immune system, jumpstart gut function, and seed a healthy gut microbiome in the first few days of life. The bioactives found in colostrum are essential for a newborn's health, growth and vitality. Colostrum strengthens a baby's immune system and is filled with white blood cells to protect it from infection.
Lactoferrin (LF), also known as lactotransferrin (LTF), is a multifunctional protein of the transferrin family. Lactoferrin is a globular glycoprotein with a molecular mass of about 80 kDa that is widely represented in various secretory fluids, such as milk, saliva, tears, and nasal secretions. Lactoferrin is also present in secondary granules of PMNs and is secreted by some acinar cells. Lactoferrin can be purified from milk or produced recombinantly. Human colostrum has the highest concentration, followed by human milk, then cow milk (150 mg/L).
Protein splicing is an intramolecular reaction of a particular protein in which an internal protein segment is removed from a precursor protein with a ligation of C-terminal and N-terminal external proteins on both sides. The splicing junction of the precursor protein is mainly a cysteine or a serine, which are amino acids containing a nucleophilic side chain. The protein splicing reactions which are known now do not require exogenous cofactors or energy sources such as adenosine triphosphate (ATP) or guanosine triphosphate (GTP). Normally, splicing is associated only with pre-mRNA splicing. This precursor protein contains three segments—an N-extein followed by the intein followed by a C-extein. After splicing has taken place, the resulting protein contains the N-extein linked to the C-extein; this splicing product is also termed an extein.
Antimicrobial peptides (AMPs), also called host defence peptides (HDPs) are part of the innate immune response found among all classes of life. Fundamental differences exist between prokaryotic and eukaryotic cells that may represent targets for antimicrobial peptides. These peptides are potent, broad spectrum antimicrobials which demonstrate potential as novel therapeutic agents. Antimicrobial peptides have been demonstrated to kill Gram negative and Gram positive bacteria, enveloped viruses, fungi and even transformed or cancerous cells. Unlike the majority of conventional antibiotics it appears that antimicrobial peptides frequently destabilize biological membranes, can form transmembrane channels, and may also have the ability to enhance immunity by functioning as immunomodulators.
C5 convertase is an enzyme belonging to a family of serine proteases that play key role in the innate immunity. It participates in the complement system ending with cell death.
Tyrocidine is a mixture of cyclic decapeptides produced by the bacteria Brevibacillus brevis found in soil. It can be composed of 4 different amino acid sequences, giving tyrocidine A–D. Tyrocidine is the major constituent of tyrothricin, which also contains gramicidin. Tyrocidine was the first commercially available antibiotic, but has been found to be toxic toward human blood and reproductive cells. The function of tyrocidine within its host B. brevis is thought to be regulation of sporulation.
Iron-binding proteins are carrier proteins and metalloproteins that are important in iron metabolism and the immune response. Iron is required for life.
Dermcidin is a protein with 110 amino acids that in humans is encoded by the DCD gene. The full-length protein produces derived peptides as proteolysis-inducing factor (PIF) and other anti-microbial peptides, secreted by human eccrine sweat glands onto the skin as a part of the innate host defense of the immune system. PIF is involved in muscular proteolysis.
Cathelicidin antimicrobial peptide (CAMP) is an antimicrobial peptide encoded in the human by the CAMP gene. The active form is LL-37. In humans, CAMP encodes the peptide precursor CAP-18, which is processed by proteinase 3-mediated extracellular cleavage into the active form LL-37.
Ovotransferrin (conalbumin) is a glycoprotein of egg white albumen. Egg white albumen is composed of multiple proteins, of which ovotransferrin is the most heat reliable. It has a molecular weight of 76,000 daltons and contains about 700 amino acids. Ovotransferrin makes up approximately 13% of egg albumen. As a member of the transferrin and metalloproteinase family, ovotransferrin has been found to possess antibacterial and antioxidant and immunomodulatory properties, arising primarily through its iron (Fe3+) binding capacity by locking away a key biochemical component necessary for micro-organismal survival. Bacteria starved of iron are rendered incapable of moving, making ovotransferrin a potent bacteriostatic.
N-formyl peptide receptor 2 (FPR2) is a G-protein coupled receptor (GPCR) located on the surface of many cell types of various animal species. The human receptor protein is encoded by the FPR2 gene and is activated to regulate cell function by binding any one of a wide variety of ligands including not only certain N-Formylmethionine-containing oligopeptides such as N-Formylmethionine-leucyl-phenylalanine (FMLP) but also the polyunsaturated fatty acid metabolite of arachidonic acid, lipoxin A4 (LXA4). Because of its interaction with lipoxin A4, FPR2 is also commonly named the ALX/FPR2 or just ALX receptor.
Beta-defensin 2 (BD-2) also known as skin-antimicrobial peptide 1 (SAP1) is a peptide that in humans is encoded by the DEFB4 gene.
Interferon omega-1 is a protein that is encoded by the IFNW1 gene.
Cecropins are antimicrobial peptides. They were first isolated from the hemolymph of Hyalophora cecropia, whence the term cecropin was derived. Cecropins lyse bacterial cell membranes; they also inhibit proline uptake and cause leaky membranes.
Protegrins are small peptides containing 16-18 amino acid residues. Protegrins were first discovered in porcine leukocytes and were found to have antimicrobial activity against bacteria, fungi, and some enveloped viruses. The amino acid composition of protegrins contains six positively charged arginine residues and four cysteine residues. Their secondary structure is classified as cysteine-rich β-sheet antimicrobial peptides, AMPs, that display limited sequence similarity to certain defensins and tachyplesins. In solution, the peptides fold to form an anti-parallel β-strand with the structure stabilized by two cysteine bridges formed among the four cysteine residues. Recent studies suggest that protegrins can bind to lipopolysaccharide, a property that may help them to insert into the membranes of gram-negative bacteria and permeabilize them.
Feline coronavirus (FCoV) is a positive-stranded RNA virus that infects cats worldwide. It is a coronavirus of the species Alphacoronavirus 1, which includes canine coronavirus (CCoV) and porcine transmissible gastroenteritis coronavirus (TGEV). FCoV has two different forms: feline enteric coronavirus (FECV), which infects the intestines, and feline infectious peritonitis virus (FIPV), which causes the disease feline infectious peritonitis (FIP).
The respiratory tract antimicrobial defense system is a layered defense mechanism which relies on components of both the innate and adaptive immune systems to protect the lungs and the rest of the respiratory tract against inhaled microorganisms.
Lactoperoxidase is a peroxidase enzyme secreted from mammary, salivary, tears and other mucosal glands including the lungs, bronchii and nose that function as a natural, first line of defense against bacteria and viral agents. Lactoperoxidase is a member of the heme peroxidase family of enzymes. In humans, lactoperoxidase is encoded by the LPO gene.
Amidorphin is an endogenous, C-terminally amidated, opioid peptide generated as a cleavage product of proenkephalin A in some mammalian species; in humans and most other species, the peptide is 1 residue longer and is not amidated. Amidorphin is widely distributed in the mammalian brain, with particularly high concentrations found in the striatum, and outside of the brain in adrenal medulla and posterior pituitary. The 26-residue peptide named amidorphin is found in several species including bovine, sheep, and pig. Humans and commonly studied lab animals produce a 27-residue peptide that does not have an amidated C-terminal residue; this is due to the absence of a Gly in the precursor sequence and replacement with Ala, which is not a substrate for the amidating enzyme. The properties of the 27-residue peptide are presumably similar to those of amidorphin, although this has not been adequately tested.
References
- 1 2 Wakabayashi H, Takase M, Tomita M (2003). "Lactoferricin derived from milk protein lactoferrin" (PDF). Current Pharmaceutical Design. 9 (16): 1277–1287. doi:10.1007/s13594-013-0153-2. PMID 12769736. S2CID 85279971.
- ↑ Eliassen LT, Berge G, Sveinbjørnsson B, Svendsen JS, Vorland LH, Rekdal Ø (2002). "Evidence for a direct antitumor mechanism of action of bovine lactoferricin". Anticancer Research. 22 (5): 2703–2710. PMID 12529985.
- ↑ Bruni N, Capucchio MT, Biasibetti E, Pessione E, Cirrincione S, Giraudo L, et al. (June 2016). "Antimicrobial Activity of Lactoferrin-Related Peptides and Applications in Human and Veterinary Medicine". Molecules. 21 (6): 752. doi: 10.3390/molecules21060752 . PMC 6273662 . PMID 27294909.
- ↑ Gifford JL, Hunter HN, Vogel HJ (November 2005). "Lactoferricin: a lactoferrin-derived peptide with antimicrobial, antiviral, antitumor and immunological properties". Cellular and Molecular Life Sciences. 62 (22): 2588–2598. doi:10.1007/s00018-005-5373-z. PMC 11139180 . PMID 16261252.
- ↑ Hunter HN, Demcoe AR, Jenssen H, Gutteberg TJ, Vogel HJ (August 2005). "Human lactoferricin is partially folded in aqueous solution and is better stabilized in a membrane mimetic solvent". Antimicrobial Agents and Chemotherapy. 49 (8): 3387–3395. doi:10.1128/AAC.49.8.3387-3395.2005. PMC 1196233 . PMID 16048952.