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Mixed Inhibition
Mixed inhibition is a type of enzyme inhibition in which the inhibitor may bind to the enzyme whether or not the enzyme has already bound the substrate but has a greater affinity for one state or the other. It is called "mixed" because it can be seen as a conceptual "mixture" of competitive inhibition, in which the inhibitor can only bind the enzyme if the substrate ''has not'' already bound, and uncompetitive inhibition, in which the inhibitor can only bind the enzyme if the substrate ''has'' already bound. If the ability of the inhibitor to bind the enzyme is ''exactly the same'' whether or not the enzyme has already bound the substrate, it is known as a non-competitive inhibitor. Non-competitive inhibition is sometimes thought of as a special case of mixed inhibition. In mixed inhibition, the inhibitor binds to an allosteric site, i.e. a site different from the active site where the substrate binds. However, not all inhibitors that bind at allosteric sites are mixed inhibito ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mixed Inhibition
Mixed inhibition is a type of enzyme inhibition in which the inhibitor may bind to the enzyme whether or not the enzyme has already bound the substrate but has a greater affinity for one state or the other. It is called "mixed" because it can be seen as a conceptual "mixture" of competitive inhibition, in which the inhibitor can only bind the enzyme if the substrate ''has not'' already bound, and uncompetitive inhibition, in which the inhibitor can only bind the enzyme if the substrate ''has'' already bound. If the ability of the inhibitor to bind the enzyme is ''exactly the same'' whether or not the enzyme has already bound the substrate, it is known as a non-competitive inhibitor. Non-competitive inhibition is sometimes thought of as a special case of mixed inhibition. In mixed inhibition, the inhibitor binds to an allosteric site, i.e. a site different from the active site where the substrate binds. However, not all inhibitors that bind at allosteric sites are mixed inhibito ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3-Mercaptopropionic Acid
3-Mercaptopropionic acid (3-MPA) is an organosulfur compound with the formula HSCH2CH2CO2H. It is a bifunctional molecule, containing both carboxylic acid and thiol groups. It is a colorless oil. It is derived from the addition of hydrogen sulfide to acrylic acid. Reactions and uses It is competitive inhibitor of glutamate decarboxylase, and therefore acts as a convulsant. It has higher potency and faster onset of action compared to allylglycine. It is used to prepare hydrophilic gold nanoparticles, exploiting the affinity of gold for sulfur ligands. See also * Allylglycine * Thiolactic acid Thiolactic acid is the organosulfur compound with the formula HSCH2CO2H. The molecule contains both carboxylic acid and thiol functional groups. It is structurally related to lactic acid by the interchange of SH for OH. It is a colorless oil. T ... (2-mercaptopropionic acid) References Convulsants Glutamate decarboxylase inhibitors Thiols Propionic acids {{Organic-c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme Kinetics
Enzyme kinetics is the study of the rates of enzyme-catalysed chemical reactions. In enzyme kinetics, the reaction rate is measured and the effects of varying the conditions of the reaction are investigated. Studying an enzyme's kinetics in this way can reveal the catalytic mechanism of this enzyme, its role in metabolism, how its activity is controlled, and how a drug or a modifier ( inhibitor or activator) might affect the rate. An enzyme (E) is typically a protein molecule that promotes a reaction of another molecule, its substrate (S). This binds to the active site of the enzyme to produce an enzyme-substrate complex ES, and is transformed into an enzyme-product complex EP and from there to product P, via a transition state ES*. The series of steps is known as the mechanism: : E + S ⇄ ES ⇄ ES* ⇄ EP ⇄ E + P This example assumes the simplest case of a reaction with one substrate and one product. Such cases exist: for example, a mutase such as phosphoglucomutase ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KLK7
Kallikrein-related peptidase 7 (KLK7) is a serine protease that in humans is encoded by the ''KLK7'' gene. KLK7 was initially purified from the epidermis and characterised as stratum corneum chymotryptic enzyme (SCCE). It was later identified as the seventh member of the human kallikrein family, which includes fifteen homologous serine proteases located on chromosome 19 (19q13). Gene Alternative splicing of the ''KLK7'' gene results in two transcript variants encoding the same protein. Function KLK7 is secreted as an inactive zymogen in the stratum granulosum layer of the epidermis, requiring proteolytic cleavage of the short N-terminal pro-region to liberate activated enzyme. This may be performed by KLK5 or matriptase, which are ''in vitro'' activators of KLK7. Once active, KLK7 is able to cleave desmocollin and corneodesmosin. These proteins constitute the extracellular component of corneodesmosomes, intercellular cohesive structures which link the intermediate filaments ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KLK6
Kallikrein-6 is a protein that in humans is encoded by the ''KLK6'' gene. Function Kallikreins are a subgroup of serine proteases having diverse physiological functions. Growing evidence suggests that many kallikreins are implicated in carcinogenesis and some have potential as novel cancer and other disease biomarkers. This gene is one of the fifteen kallikrein subfamily members located in a cluster on chromosome 19. The encoded enzyme is regulated by steroid hormones. In tissue culture, the enzyme has been found to generate amyloidogenic fragments from the amyloid precursor protein, suggesting a potential for involvement in Alzheimer's disease. Multiple alternatively spliced transcript variants that encode different isoforms have been identified for this gene. References Further reading * * * * * * * * * * * * * * * * * * * External links * The MEROPS MEROPS is an online database for peptidases (also known as proteases, proteinases and proteol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KLK5
Kallikrein-5, formerly known as stratum corneum tryptic enzyme (SCTE), is a serine protease expressed in the epidermis. In humans it is encoded by the ''KLK5'' gene. This gene is one of the fifteen kallikrein subfamily members located in a cluster on chromosome 19. Its expression is up-regulated by estrogens and progestins. Alternative splicing results in multiple transcript variants encoding the same protein. KLK5 has been suggested to regulate cell shedding (desquamation) in conjunction with KLK7 and KLK14, given its ability to degrade proteins which form the extracellular component of cell junctions in the stratum corneum. It is proposed that KLK5 regulates this process since it is able to self-activate in addition to activating KLK7 and KLK14. References Further reading * * * * * * * * * * * * * * * * * External links * The MEROPS MEROPS is an online database for peptidases (also known as proteases, proteinases and proteolytic enzymes) and their inhibitors. The c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KLK4
Kallikrein-related peptidase 4 is a protein which in humans is encoded by the ''KLK4'' gene. Kallikreins are a subgroup of serine proteases having diverse physiological functions. Growing evidence suggests that many kallikreins are implicated in carcinogenesis and some have potential as novel cancer and other disease biomarkers. In particular, they may serve as biomarkers for both prostate cancer and breast cancer. This gene is one of the fifteen kallikrein subfamily members located in a cluster on chromosome 19. In some tissues its expression is hormonally regulated. The expression pattern of a similar mouse protein in murine developing teeth supports a role for the protein in the degradation of enamel proteins. Alternate splice variants for this gene have been described, but their biological validity has not been determined. References Further reading * * * * * * * * * * * * * * * * * * * External links * The MEROPS MEROPS is an online database for peptidases (also kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KLK3
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] |
KLK2
Kallikrein-2 is a protein that in humans is encoded by the ''KLK2'' gene, and is particularly associated with prostatic tissue. References Further reading * * * * * * * * * * * * * * * * * * * External links * The MEROPS MEROPS is an online database for peptidases (also known as proteases, proteinases and proteolytic enzymes) and their inhibitors. The classification scheme for peptidases was published by Rawlings & Barrett in 1993, and that for protein inhibitor ... online database for peptidases and their inhibitorsS01.161 * {{gene-19-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biflavonoid
Biflavonoids are a type of flavonoids with the general formula scheme (C6-C3-C6)2. Examples * Amentoflavone (bis-apigenin coupled at 8 and 3' positions) * Lophirone L and lophirone M found in ''Lophira alata'' * Sulcatone A, a naturally occurring biflavonoid isolated from '' Ouratea sulcata''. Extracts of the leaves of this plant, used with and with other plant's extracts, are used in many African countries to treat some infections such as upper tract respiratory infections, dysenteria, diarrhoea and toothache. Positive antimicrobial activity has been shown in-vitro against '' Staphylococcus aureus'' and ''Bacillus subtilis''. ''Escherichia coli'' showed to be resistant in the same study. * Hinokiflavone, a cytotoxic biflavonoid from ''Toxicodendron succedaneum'', ''Juniperus sp.'', or '' Chamaecyparis obtusa'' (hinoki). * Leaflets of ''Cycas circinalis'' and '' C. revoluta'' contain biflavonoids such as (2''S'', 2′′''S'')-2,3,2′′,3′′-tetrahydro-4′,4′′′-di- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morelloflavone
Morelloflavone, an isolate of ''Garcinia dulcis'', belongs to the family of biflavonoid Biflavonoids are a type of flavonoids with the general formula scheme (C6-C3-C6)2. Examples * Amentoflavone (bis-apigenin coupled at 8 and 3' positions) * Lophirone L and lophirone M found in ''Lophira alata'' * Sulcatone A, a naturally occur ...s and is an inhibitor of HMG-CoA reductase. References Flavonoids {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KLK15
Kallikrein-15 is a protein that in humans is encoded by the ''KLK15'' gene. Kallikreins are a subgroup of serine proteases having diverse physiological functions. Growing evidence suggests that many kallikreins are implicated in carcinogenesis and some have potential as novel cancer and other disease biomarkers. This gene is one of the fifteen kallikrein subfamily members located in a cluster on chromosome 19. In prostate cancer, this gene has increased expression, which indicates its possible use as a diagnostic or prognostic marker for prostate cancer. The gene contains multiple polyadenylation sites and alternative splicing results in multiple transcript variants encoding distinct isoforms. References Further reading * * * * * * * * * * External links * The MEROPS MEROPS is an online database for peptidases (also known as proteases, proteinases and proteolytic enzymes) and their inhibitors. The classification scheme for peptidases was published by Rawlings & Barrett ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
