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A protease is an enzyme that catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. They do this by cleaving the peptide bonds within proteins by hydrolysis, a reaction where water breaks bonds. Proteases are involved in many biological functions, including digestion of ingested proteins, protein catabolism, and cell signaling.
A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata. It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords. The subphylum was at one time called Urochordata, and the term urochordates is still sometimes used for these animals. They are the only chordates that have lost their myomeric segmentation, with the possible exception of the 'seriation of the gill slits'. However, doliolids still display segmentation of the muscle bands.
During fertilization, a sperm must first fuse with the plasma membrane and then penetrate the female egg cell to fertilize it. Fusing to the egg cell usually causes little problem, whereas penetrating through the egg's hard shell or extracellular matrix can be more difficult. Therefore, sperm cells go through a process known as the acrosome reaction, which is the reaction that occurs in the acrosome of the sperm as it approaches the egg.
Serine proteases are enzymes that cleave peptide bonds in proteins. Serine serves as the nucleophilic amino acid at the (enzyme's) active site. They are found ubiquitously in both eukaryotes and prokaryotes. Serine proteases fall into two broad categories based on their structure: chymotrypsin-like (trypsin-like) or subtilisin-like.
Ascidiacea, commonly known as the ascidians or sea squirts, is a paraphyletic class in the subphylum Tunicata of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer "tunic" made of a polysaccharide.
Acrosin is a digestive enzyme that acts as a protease. In humans, acrosin is encoded by the ACR gene. Acrosin is released from the acrosome of spermatozoa as a consequence of the acrosome reaction. It aids in the penetration of the Zona Pellucida.
Enteropeptidase is an enzyme produced by cells of the duodenum and is involved in digestion in humans and other animals. Enteropeptidase converts trypsinogen into its active form trypsin, resulting in the subsequent activation of pancreatic digestive enzymes. Absence of enteropeptidase results in intestinal digestion impairment.
A catalytic triad is a set of three coordinated amino acids that can be found in the active site of some enzymes. Catalytic triads are most commonly found in hydrolase and transferase enzymes. An acid-base-nucleophile triad is a common motif for generating a nucleophilic residue for covalent catalysis. The residues form a charge-relay network to polarise and activate the nucleophile, which attacks the substrate, forming a covalent intermediate which is then hydrolysed to release the product and regenerate free enzyme. The nucleophile is most commonly a serine or cysteine amino acid, but occasionally threonine or even selenocysteine. The 3D structure of the enzyme brings together the triad residues in a precise orientation, even though they may be far apart in the sequence.
Benzamidine is the organic compound with the formula C6H5C(NH)NH2. It is the simplest aryl amidine. The compound is a white solid that is slightly soluble in water. It is usually handled as the hydrochloride salt, a white, water-soluble solid.
An equivalence group is a set of unspecified cells that have the same developmental potential or ability to adopt various fates. Our current understanding suggests that equivalence groups are limited to cells of the same ancestry, also known as sibling cells. Often, cells of an equivalence group adopt different fates from one another.
Disintegrin and metalloproteinase domain-containing protein 2 or Beta-fertilin is an enzyme that in humans is encoded by the ADAM2 gene.
Transmembrane protease, serine 11D is an enzyme that in humans is encoded by the TMPRSS11D gene.
Serine protease inhibitor Kazal-type 2 also known as acrosin-trypsin inhibitor is a protein that in humans is encoded by the SPINK2 gene.
Antipain is an oligopeptide that is isolated from actinomycetes and used in biochemical research as a protease inhibitor of trypsin and papain. It was discovered in 1972 and was the first natural peptide found that contained an ureylene group. Antipain can aid in prevention of coagulation in blood. It is an inhibitor of serine and cysteine proteases.
Brachyurin is an enzyme. This enzyme catalyses the Hydrolysis of proteins, with broad specificity for peptide bonds. Native collagen is cleaved about 75% of the length of the molecule from the N-terminus.
Venombin A is an enzyme. This enzyme catalyses the following chemical reaction
Limulus clotting factor overbar C is an enzyme. This enzyme catalyses the following chemical reaction
Halocyaminess are antibiotic peptides isolated from the ascidian Halocynthia roretzi.
The PA clan is the largest group of proteases with common ancestry as identified by structural homology. Members have a chymotrypsin-like fold and similar proteolysis mechanisms but can have identity of <10%. The clan contains both cysteine and serine proteases. PA clan proteases can be found in plants, animals, fungi, eubacteria, archaea and viruses.
The ascidian mitochondrial code is a genetic code found in the mitochondria of Ascidia.
References
- ↑ Sawada H, Yokosawa H, Ishii S (March 1984). "Purification and characterization of two types of trypsin-like enzymes from sperm of the ascidian (Prochordata) Halocynthia roretzi. Evidence for the presence of spermosin, a novel acrosin-like enzyme". The Journal of Biological Chemistry. 259 (5): 2900–4. PMID 6365918.
- ↑ Sawada H, Yokosawa H, Someno T, Saino T, Ishii S (September 1984). "Evidence for the participation of two sperm proteases, spermosin and acrosin, in fertilization of the ascidian, Halocynthia roretzi: inhibitory effects of leupeptin analogs on enzyme activities and fertilization". Developmental Biology. 105 (1): 246–9. doi:10.1016/0012-1606(84)90281-1. PMID 6381175.
- ↑ Sawada H, Iwasaki K, Kihara-Negishi F, Ariga H, Yokosawa H (May 1996). "Localization, expression, and the role in fertilization of spermosin, an ascidian sperm trypsin-like protease". Biochemical and Biophysical Research Communications. 222 (2): 499–504. doi:10.1006/bbrc.1996.0773. PMID 8670234.
- ↑ Sawada H, Someno T (October 1996). "Substrate specificity of ascidian sperm trypsin-like proteases, spermosin and acrosin". Molecular Reproduction and Development. 45 (2): 240–3. doi:10.1002/(SICI)1098-2795(199610)45:2<240::AID-MRD18>3.0.CO;2-4. PMID 8914083.
