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Semenogelin
Semenogelin is a protein that is involved in the formation of a gel matrix that encases ejaculated spermatozoa, preventing capacitation. It blocks capacitation mainly via inhibition of reactive oxygen species (ROS) generation. Proteolysis by prostate-specific antigen (PSA) breaks down the gel matrix and allows the spermatozoa to move more freely. The cleavage products of the semenogelins constitute the main antibacterial components in human seminal plasma. There are two variants of the semenogelin protein: semenogelin 1 and semenogelin 2 Semenogelin-2 is a protein that in humans is encoded by the ''SEMG2'' gene. The secreted protein encoded by this gene is involved in the formation of a gel matrix that encases ejaculated spermatozoa. Proteolysis by the prostate-specific antigen ( .... Semenogelin along with prostate-specific antigen, are commonly tested for during crime scene investigation. References {{Reflist Proteins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semenogelin 2
Semenogelin-2 is a protein that in humans is encoded by the ''SEMG2'' gene. The secreted protein encoded by this gene is involved in the formation of a gel matrix that encases ejaculated spermatozoa. Proteolysis by the prostate-specific antigen (PSA) breaks down the gel matrix and allows the spermatozoa to move more freely. The encoded protein is found in lesser abundance than a similar semenogelin protein. The genes encoding these two semenogelin proteins are found in a cluster on chromosome 20. See also *Semenogelin Semenogelin is a protein that is involved in the formation of a gel matrix that encases ejaculated spermatozoa, preventing capacitation. It blocks capacitation mainly via inhibition of reactive oxygen species (ROS) generation. Proteolysis by prost ... References Further reading * * * * * * * * * * * * * * * * * * {{gene-20-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semenogelin 1
Semenogelin-1 is a protein that in humans is encoded by the ''SEMG1'' gene. The protein encoded by this gene is the predominant protein in semen. The encoded secreted protein is involved in the formation of a gel matrix that encases ejaculated spermatozoa. The prostate-specific antigen (PSA) protease processes this protein into smaller peptides, with each possibly having a separate function. The proteolysis process breaks down the gel matrix and allows the spermatozoa to move more freely. Two transcript variants encoding different isoforms have been found for this gene. See also *Semenogelin Semenogelin is a protein that is involved in the formation of a gel matrix that encases ejaculated spermatozoa, preventing capacitation. It blocks capacitation mainly via inhibition of reactive oxygen species (ROS) generation. Proteolysis by prost ... References Further reading * * * * * * * * * * * * * * * * * * {{gene-20-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prostate-specific Antigen
Prostate-specific antigen (PSA), also known as gamma-seminoprotein or kallikrein-3 (KLK3), P-30 antigen, is a glycoprotein enzyme encoded in humans by the ''KLK3'' gene. PSA is a member of the kallikrein-related peptidase family and is secreted by the epithelial cells of the prostate gland. PSA is produced for the ejaculate, where it liquefies semen in the seminal coagulum and allows sperm to swim freely. It is also believed to be instrumental in dissolving cervical mucus, allowing the entry of sperm into the uterus. PSA is present in small quantities in the serum of men with healthy prostates, but is often elevated in the presence of prostate cancer or other prostate disorders. PSA is not uniquely an indicator of prostate cancer, but may also detect prostatitis or benign prostatic hyperplasia. Medical uses Prostate cancer Screening Clinical practice guidelines for prostate cancer screening vary and are controversial, in part due to uncertainty as to whether the benefits o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, providing structure to cells and organisms, and transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the nucleotide sequence of their genes, and which usually results in protein folding into a specific 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides. The individual amino acid residues are bonded together by peptide bonds and adjacent amino acid residues. The sequence of amino acid residue ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capacitation
Capacitation is the penultimate step in the maturation of mammalian spermatozoa and is required to render them competent to fertilize an oocyte. This step is a biochemical event; the sperm move normally and look mature prior to capacitation. ''In vivo'', capacitation occurs after ejaculation, when the spermatozoa leave the vagina and enter the superior female reproductive tract. The uterus aids in the steps of capacitation by secreting sterol-binding albumin, lipoproteins, and proteolytic and glycosidasic enzymes such as heparin. For purposes of ''in vitro'' fertilization, capacitation occurs by incubating spermatozoa that have either undergone ejaculation or have been extracted from the epididymis and incubated in a defined medium for several hours. There are different techniques to perform the capacitation step: simple washing, migration (swim-up), density gradients, and filter. The objective is to isolate as many motile spermatozoa as possible and to eliminate non-motile or d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reactive Oxygen Species
In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (). Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen. The reduction of molecular oxygen () produces superoxide (), which is the precursor to most other reactive oxygen species: :O2 + e^- -> \ ^\bullet O2- Dismutation of superoxide produces hydrogen peroxide (): :2 H+ + \ ^\bullet O2^- + \ ^\bullet O2^- -> H2O2 + O2 Hydrogen peroxide in turn may be partially reduced, thus forming hydroxide ions and hydroxyl radicals (), or fully reduced to water: :H2O2 + e^- -> HO^- + \ ^\bullet OH :2 H+ + 2 e- + H2O2 -> 2 H2O In a biological context, ROS are byproducts of the normal metabolism of oxygen. ROS have roles in cell signaling and homeostasis. ROS are intrinsic to cellular functioning, and are present at low and stationary levels in normal cells. In plants, ROS are involved in metabolic processes related to photoprotection and toleran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
