Category: The Science
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Kynureninase or L-Kynurenine hydrolase (KYNU) is part of the pathway for the catabolism of Trp and the biosynthesis of NAD cofactors from tryptophan (Trp).
Kynureninase or L-Kynurenine hydrolase (KYNU) (EC 3.7.1.3) is a PLP dependent enzyme that catalyses the cleavage of kynurenine (Kyn) into anthranilic acid (Ant). It can also act on 3-hydroxykynurenine (to produce 3-hydroxyanthranilate) and some other (3-arylcarbonyl)-alanines. Note: 3-Hydroxykynurenine is a metabolite of tryptophan, which filters UV light in the human lens. It is one of two pigments identified as responsible for the goldenrod crab spider‘s (Misumena vatia) yellow coloration. 3-Hydroxyanthranilic acid is an intermediate in the metabolism of tryptophan. It…
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Ommochrome (visual pigment) and Kynurenine (a metabolite of the amino acid l-tryptophan used in the production of niacin)
Ommochrome (or visual pigment) refers to several biological pigments that occur in the eyes of crustaceans and insects. The eye color is determined by the ommochromes. Ommochromes are also found in the chromatophores of cephalopods, and in spiders. Ommochromes are metabolites of tryptophan, via kynurenine and 3-hydroxykynurenine. They are responsible for a wide variety of colors, ranging from yellow over red and brown to black. Lighter colors tend to be generated by ommatins,…
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Albert Imre Szent-Györgyi – From Transylvania to Woods Hole (Vitamin C, Fumaric Acid, WWI, WWII, Vietnam War, Actin, Myosin, Muscles, Adrenal glands, Cancer, a Nobel prize, Apollonians and Dionysians, and something called the Constitution for the Federation of Earth)
Albert Imre Szent-Györgyi[a] de Nagyrápolt (Hungarian: nagyrápolti Szent-Györgyi Albert Imre; September 16, 1893 – October 22, 1986) was a Hungarian biochemist who won the Nobel Prize in Physiology or Medicine in 1937. He is credited with first isolating vitamin C and discovering the components and reactions of the citric acid cycle. He was also active in the Hungarian Resistance during World War II, and entered Hungarian politics after the…
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Streptomyces is the largest antibiotic-producing genus, producing antibacterial, antifungal, and antiparasitic drugs, and also a wide range of other bioactive compounds, such as immunosuppressants.
Streptomyces is the largest genus of Actinomycetota, and the type genus of the family Streptomycetaceae. Over 700 species of Streptomyces bacteria have been described. As with the other Actinomycetota, streptomycetes are gram-positive, and have very large genomes with high GC content. Found predominantly in soil and decaying vegetation, most streptomycetes produce spores, and are noted for their distinct “earthy” odor that results from production of a volatile metabolite, geosmin. Different strains of the…
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Sterol carrier proteins (aka nonspecific lipid transfer proteins)
These proteins are different from plant nonspecific lipid transfer proteins but structurally similar to small proteins of unknown function from Thermus thermophilus. This domain is involved in binding sterols. The human sterol carrier protein 2 (SCP2) is a basic protein that is believed to participate in the intracellular transport of cholesterol and various other lipids. Human…
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Glucuronic acid is a uronic acid that was first isolated from urine
Glucuronic acid (from Greek γλεῦκος “wine, must” and οὖρον “urine“) is a uronic acid that was first isolated from urine (hence the name”uronic acid”). It is found in many gums such as gum arabic (approx. 18%), xanthan, and kombucha tea and is important for the metabolism of microorganisms, plants and animals. Not to be confused with Gluconic acid (Gluconic acid occurs naturally in fruit, honey, and wine. As a food additive E574, it is now known as an acidity regulator.…
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Fischer-Fantuzzi L, Vesco C. Deletion of 43 amino acids in the NH2-terminal half of the large tumor antigen of simian virus 40 results in a non-karyophilic protein capable of transforming established cells. Proc Natl Acad Sci U S A. 1985
Abstract We have characterized a simian virus 40 (SV40) mutant, derived from the viral DNA insertion present in simian cell transformants, which carries a deletion affecting the NH2-terminal region of the SV40 large tumor antigen. This mutant protein is 6% smaller than normal, has lost the typical nuclear localization of the SV40 large tumor antigen,…
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Proline and a few other notes
Proline (symbol Pro or P) is an organic acid classed as a proteinogenic amino acid (used in the biosynthesis of proteins), although it does not contain the amino group -NH2 but is rather a secondary amine. The secondary amine nitrogen is in the protonated form (NH2+) under biological conditions, while the carboxyl group is in the deprotonated −COO− form. The “side chain” from the α carbon connects to the nitrogen forming a pyrrolidine loop, classifying it…
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Serine
Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH+3 form under biological conditions), a carboxyl group (which is in the deprotonated −COO− form under biological conditions), and a side chain consisting of a hydroxymethyl group, classifying it as a polar amino acid. It can be synthesized in the human body under normal physiological circumstances, making…
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Opioid growth factor receptor
Opioid growth factor receptor, also known as OGFr or the ζ-opioid receptor, is a protein which in humans is encoded by the OGFR gene. The protein encoded by this gene is a receptor for opioid growth factor (OGF), also known as [Met(5)]-enkephalin. The endogenous ligand is thus a known opioid peptide, and OGFr was originally discovered and named as a new opioid receptor zeta (ζ). However it was…
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Cells in the APUD system may include melanocytes
Melanocytes are melanin-producing neural crest-derived cells located in the bottom layer (the stratum basale) of the skin’s epidermis, the middle layer of the eye (the uvea), the inner ear, vaginal epithelium, meninges, bones, and heart. Melanin is a dark pigment primarily responsible for skin color. Once synthesized, melanin is contained in special organelles called melanosomes which can be transported to nearby keratinocytes to induce pigmentation. Thus darker skin tones have more melanosomes present than lighter skin tones. Functionally, melanin serves as protection…
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Adenohypophysis regulates several physiological processes, including stress, growth, reproduction, and lactation
A major organ of the endocrine system, the anterior pituitary (also called the adenohypophysis or pars anterior) is the glandular, anterior lobe that together with the posterior lobe (posterior pituitary, or the neurohypophysis) makes up the pituitary gland (hypophysis). The anterior pituitary regulates several physiological processes, including stress, growth, reproduction, and lactation. Proper functioning of the anterior pituitary and of the organs it regulates can often be ascertained via blood tests that measure hormone levels. Structure The pituitary gland sits in a…
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Pulmonary neuroendocrine cells
Neuroendocrine cells are cells that receive neuronal input (through neurotransmitters released by nerve cells or neurosecretory cells) and, as a consequence of this input, release messenger molecules (hormones) into the blood. In this way they bring about an integration between the nervous system and the endocrine system, a process known as neuroendocrine integration. An example of a neuroendocrine cell is a cell…
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Homovanillic acid (HVC) and Vanillylmandelic acid (VMA)
Homovanillic acid (HVA) is a major catecholamine metabolite that is produced by a consecutive action of monoamine oxidase and catechol-O-methyltransferase on dopamine. Homovanillic acid is used as a reagent to detect oxidative enzymes, and is associated with dopamine levels in the brain. In psychiatry and neuroscience, brain and cerebrospinal fluid levels of HVA are measured as a marker of metabolic stress caused by 2-deoxy-D-glucose. HVA presence supports a diagnosis of neuroblastoma and malignant pheochromocytoma. Fasting plasma levels of HVA are known to be…
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Isaac Asimov’s Thiotimoline
Thiotimoline is a fictitious chemical compound conceived by American biochemist and science fiction author Isaac Asimov. Isaac Asimov (1920 – 1992) was an American writer and professor of biochemistry at Boston University. During his lifetime, Asimov was considered one of the “Big Three” science fiction writers, along with Robert A. Heinlein and Arthur C. Clarke. A prolific writer, he wrote or edited more than 500 books. He also wrote an estimated 90,000…
