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Ophanin
Ophanin is a toxin found in the venom of the King Cobra (''Ophiophagus hannah''), which lives throughout South East Asia. This toxin belongs to the cysteine-rich secretory protein (CRISP) family. Ophanin weakly blocks the contraction of smooth muscles elicited by high potassium-induced depolarization, suggesting that it inhibits voltage-dependent calcium channels. Etymology The toxin was named ''ophanin'' after the snake whose venom it is derived from, the King Cobra (''Ophiophagus hannah''). Sources Ophanin is produced in the venom glands of the King Cobra (''O. Hannah''). Although the venom has relatively low toxicity, this is compensated by the high amounts of it injected into the prey for each bite. Chemistry Structure Ophanin was successfully isolated from ''O. Hannah'' venom by gel filtration and cation-exchange chromatography. Its molecular weight is 25 kDa (from positions 19 – 239), which conforms to the molecular mass predicted from its cDNA sequences. Hom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triflin
Triflin is a cysteine-rich secretory protein (CRISP), which is excreted by the venom gland of the Habu snake (''Trimeresurus flavoviridis''). Triflin reduces high potassium-induced smooth muscle contraction, suggesting a blocking effect on L-type calcium channels. Sources Triflin is a toxin derived from snake venom. The toxin is produced in the gland of the Habu snake, ''Trimeresurus flavoviridis''. Chemistry Triflin is a cysteine-rich secretory protein, which means it belongs to the CRISP family. This is a group of single chain polypeptides found in various organisms. Triflin weighs 25 kDa and consists of 221 amino-acid residues. The first 163 residues of the N-terminal domain forms an α-β-α sandwich core. This domain is comparable with group 1 plant pathogenesis-related protein (PR-1). The C-terminal domain, has five disulfide bridges. This domain is responsible for the selectivity of the protein and consists of two subdomains: N-terminal subdomain (Cys 167 to Cys 179) a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latisemin
Latisemin is a cysteine-rich secretory protein that can be isolated from the venom of the Black-banded sea krait, a sea snake indigenous to the warmer waters of the western Pacific Ocean. It is a toxin that inhibits cyclic nucleotide-gated ion channels and blocks L-type calcium channels, thereby reducing smooth muscle contraction. Sources Latisemin is a component of the venom produced by the Erabu sea snake (''Laticauda semifasciata'') of the family Elapidae and the Laticauda genus. These sea snakes inhabit coral reef areas in the seas of Southern Japan, Southeast Asia, and Australia. Though highly venomous, this snake is comparatively unaggressive, and is in fact caught and eaten in Erabu soup in Japan. Biochemistry Latisemin has a molecular weight of 24 kDa and consists of 217 amino acids. It belongs to the CRISP (cysteine-rich secretory protein) glycoprotein subfamily, which are single chain polypeptides containing strictly conserved cysteines (cysteines not oxidised to c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ablomin
Ablomin is a toxin present in the venom of the Japanese Mamushi snake, which blocks L-type voltage-gated calcium channels. Etymology The protein ablomin is a component of the venom of the Japanese Mamushi snake, ''Gloydius blomhoffii''. The term ‘ablomin’ is an acronym derived from ''Agkistrodon blomhoffi'', an old name for this snake. Sources The protein can be found in the venom of the Japanese Mamushi snake, a member of the Viperidae family. Chemistry Ablomin is part of the Cystein-Rich Secretory Protein (CRISP) family. CRISPs comprise a particular group of snake venom proteins distributed among the venom of several families of snakes, such as elapids, colubrids and vipers. The protein exists of 240 amino acids, coded by an mRNA of 1336 base pairs. Structurally, it is composed of three distinct regions: an N-terminal protein domain, a hinge region and a C-terminal cystein-rich domain. It has a molecular mass of 25 kDa The dalton or unified atomic mass unit (sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triflin
Triflin is a cysteine-rich secretory protein (CRISP), which is excreted by the venom gland of the Habu snake (''Trimeresurus flavoviridis''). Triflin reduces high potassium-induced smooth muscle contraction, suggesting a blocking effect on L-type calcium channels. Sources Triflin is a toxin derived from snake venom. The toxin is produced in the gland of the Habu snake, ''Trimeresurus flavoviridis''. Chemistry Triflin is a cysteine-rich secretory protein, which means it belongs to the CRISP family. This is a group of single chain polypeptides found in various organisms. Triflin weighs 25 kDa and consists of 221 amino-acid residues. The first 163 residues of the N-terminal domain forms an α-β-α sandwich core. This domain is comparable with group 1 plant pathogenesis-related protein (PR-1). The C-terminal domain, has five disulfide bridges. This domain is responsible for the selectivity of the protein and consists of two subdomains: N-terminal subdomain (Cys 167 to Cys 179) a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latisemin
Latisemin is a cysteine-rich secretory protein that can be isolated from the venom of the Black-banded sea krait, a sea snake indigenous to the warmer waters of the western Pacific Ocean. It is a toxin that inhibits cyclic nucleotide-gated ion channels and blocks L-type calcium channels, thereby reducing smooth muscle contraction. Sources Latisemin is a component of the venom produced by the Erabu sea snake (''Laticauda semifasciata'') of the family Elapidae and the Laticauda genus. These sea snakes inhabit coral reef areas in the seas of Southern Japan, Southeast Asia, and Australia. Though highly venomous, this snake is comparatively unaggressive, and is in fact caught and eaten in Erabu soup in Japan. Biochemistry Latisemin has a molecular weight of 24 kDa and consists of 217 amino acids. It belongs to the CRISP (cysteine-rich secretory protein) glycoprotein subfamily, which are single chain polypeptides containing strictly conserved cysteines (cysteines not oxidised to c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ablomin
Ablomin is a toxin present in the venom of the Japanese Mamushi snake, which blocks L-type voltage-gated calcium channels. Etymology The protein ablomin is a component of the venom of the Japanese Mamushi snake, ''Gloydius blomhoffii''. The term ‘ablomin’ is an acronym derived from ''Agkistrodon blomhoffi'', an old name for this snake. Sources The protein can be found in the venom of the Japanese Mamushi snake, a member of the Viperidae family. Chemistry Ablomin is part of the Cystein-Rich Secretory Protein (CRISP) family. CRISPs comprise a particular group of snake venom proteins distributed among the venom of several families of snakes, such as elapids, colubrids and vipers. The protein exists of 240 amino acids, coded by an mRNA of 1336 base pairs. Structurally, it is composed of three distinct regions: an N-terminal protein domain, a hinge region and a C-terminal cystein-rich domain. It has a molecular mass of 25 kDa The dalton or unified atomic mass unit (sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxin
A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849–1919) and is derived from the word toxic. Toxins can be small molecules, peptides, or proteins that are capable of causing disease on contact with or absorption by body tissues interacting with biological macromolecules such as enzymes or cellular receptors. Toxins vary greatly in their toxicity, ranging from usually minor (such as a bee sting) to potentially fatal even at extremely low doses (such as botulinum toxin). Toxins are largely secondary metabolites, which are organic compounds that are not directly involved in an organism's growth, development, or reproduction, instead often aiding it in matters of defense. Terminology Toxins are often distinguished from other chemical agents strictly based on their biological origin. Le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piscivorin
Piscivorin is a component of snake venom secreted by the Eastern Cottonmouth (''Agkistrodon piscivorus piscivorus''). It is a member of the cysteine-rich secretory protein (CRISP) family, which blocks voltage-dependent calcium channels. Etymology The name of piscivorin comes from the snake species name piscivorus, which is derived from the Latin words ''pisces'' and ''vorare'', meaning 'fish' and 'to devour' respectively. Sources Piscivorin is produced in the venom glands of the Eastern Cottonmouth snake (''Agkistrodon piscivorus piscivorus''), which populates the Eastern United States. Typically, crude venom from the Eastern Cottonmouth contains approximately 1.25% of piscivorin. Biochemistry Piscivorin belongs to the cysteine-rich secretory protein (CRISP) family, which are secreted as single-chain proteins with molecular masses between 20 and 30 kDa. They display significant amino acid sequence homology. Sixteen cysteine residues, forming 8 disulfide bonds, are strictly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reversal Potential
In a biological membrane, the reversal potential is the membrane potential at which the direction of ionic current reverses. At the reversal potential, there is no net flow of ions from one side of the membrane to the other. For channels that are permeable to only a single type of ions, the reversal potential is identical to the equilibrium potential of the ion. Equilibrium potential The equilibrium potential for an ion is the membrane potential at which there is no net movement of the ion. The flow of any inorganic ion, such as Na+ or K+, through an ion channel (since membranes are normally impermeable to ions) is driven by the electrochemical gradient for that ion. This gradient consists of two parts, the difference in the concentration of that ion across the membrane, and the voltage gradient. When these two influences balance each other, the electrochemical gradient for the ion is zero and there is no net flow of the ion through the channel; this also translates to no current ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcoplasmic Reticulum
The sarcoplasmic reticulum (SR) is a membrane-bound structure found within muscle cells that is similar to the smooth endoplasmic reticulum in other Cell (biology), cells. The main function of the SR is to store calcium ions (Ca2+). Calcium in biology, Calcium ion levels are kept relatively constant, with the concentration of calcium ions within a cell being 10,000 times smaller than the concentration of calcium ions outside the cell. This means that small increases in calcium ions within the cell are easily detected and can bring about important cellular changes (the calcium is said to be a second messenger). Calcium is used to make calcium carbonate (found in chalk) and calcium phosphate, two compounds that the body uses to make teeth and bones. This means that too much calcium within the cells can lead to hardening (calcification) of certain intracellular structures, including the mitochondrion, mitochondria, leading to cell death. Therefore, it is vital that calcium ion levels a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ryanodine
Ryanodine is a poisonous diterpenoid found in the South American plant ''Ryania speciosa'' (Salicaceae). It was originally used as an insecticide. The compound has extremely high affinity to the open-form ryanodine receptor, a group of calcium channels found in skeletal muscle, smooth muscle, and heart muscle cells. It binds with such high affinity to the receptor that it was used as a label for the first purification of that class of ion channels and gave its name to it. At nanomolar concentrations, ryanodine locks the receptor in a half-open state, whereas it fully closes them at micromolar concentration. The effect of the nanomolar-level binding is that ryanodine causes release of calcium from calcium stores as the sarcoplasmic reticulum in the cytoplasm, leading to massive muscle contractions. The effect of micromolar-level binding is paralysis. This is true for both mammals and insects. See also * Ryanoid Ryanoids are a class of insecticides which share the same mechanism ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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