examples of enzymes in the human body
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Answers:* Amylase I and II are secreted, first by the salivary glands, and then by the pancreas. They function best in a pH of 6.7-7.5, breaking bonds between carbohydrate molecules to produce disaccharides and trisaccharides. Amylase I is activated by chewing and begins the digestive process by converting starch (amylose) to maltose. Amylase II, produced by the pancreas, is only slightly different chemically and continues the process started by the salivary amylase. * Pepsin is secreted as proenzyme pepsinogen by the chief cells of the stomach and activated by hydrogen in the stomach acid, also producing hydrochloric acid at the same time. It functions best in a pH of 1.5-2.0 in order to break bonds between amino acids in proteins, producing short-chain polypeptides and destroying any pathogens that enter with the food. * Trypsin is secreted from the pancreas as proenzyme trypsinogen. It functions best in a pH of 7-8. Trypsin acts on proteins and polypeptides to produce short-chain peptides. It also activates other pancreatic proteinases. * Chymotrypsin is secreted by the pancreas as proenzyme chymotrypsinogen. It functions best in a pH of 7-8. Chymotrypsin acts on proteins and polypeptides to produce short-chain peptides. * Carboxypeptidase is secreted by the pancreas as proenzyme procarboxypeptidase. It functions best in a pH of 7-8. Carboxypeptidase acts on proteins and polypeptides to produce short-chain peptides and amino acids. * Elastase is secreted by the pancreas as proenzyme proelastase. It functions best in a pH of 7-8. Elastase targets elastin to produce short-chain peptides. * Lipase is secreted by the pancreas -- but only if bile salts are present. It functions best in a pH of 7-8. Lipase targets triglycerides to produce fatty acids and monoglycerides. Lipase also seems to be activated by the presence of Vitamin C, glutathione, and cysteine. * Nuclease is secreted by the pancreas. It functions best in a pH of 7-8. Nuclease targets nucleic acids RNA and DNA to produce nitrogen bases and simple sugars. * Enterokinase is secreted by the mucosal cells of the small intestine and reaches the lumen through disintegration of shed epithelial cells. It functions best in a pH of 7-8. Enterokinase targets trypsinogen, a proenzyme, to produce trypsin. * Maltase, sucrase, and lactase are secreted by the mucosal cells of the small intestine and found in the membrane surface of microvilli. They function best in a pH of 7-8. They respectively target the sugars maltose, sucrose, and lactose to produce monosaccharides. * Peptidase is secreted by the mucosal cells of the small intestine and found in membrane surfaces of the microvilli. It functions best in a pH of 7-8. Peptidase targets dipeptides and tripeptides to produce amino acids.
Answers:These are digestive. Lipase breaks down fats and oils. Protease breaks down proteins. Lactase breaks down dairy products. Cellulase breaks down cellulose. Amylase breaks down starches and sugars. Bromelain breaks down many foods. Papain also breaks down many foods.
Answers:It depends on where the enzyme is acting. If it is in the stomach, then likely the enzyme will function best at low pH (around 2). If the enzyme functions in the blood, it will require a more neutral pH of around 7.4. Also take into account temperature. For enzymes within the body, they will usually require normal body temperatures...somewhere from 34-39 depending on the particular location within the body.
Answers:There are thousands... How about? Tumor necrosis factor alpha (TNF-alpha), which is a multifunctional proinflammatory cytokine that belongs to the tumor necrosis factor (TNF) superfamily. This cytokine is mainly secreted by macrophages. It can bind to, and thus functions through its receptors TNFRSF1A/TNFR1 and TNFRSF1B/TNFBR. This cytokine is involved in the regulation of a wide spectrum of biological processes including cell proliferation, differentiation, apoptosis, lipid metabolism, and coagulation. This cytokine has been implicated in a variety of diseases, including autoimmune diseases, insulin resistance, and cancer. Knockout studies in mice also suggest a neuroprotective function of this cytokine. Ubiquitin, one of the most conserved proteins known. Ubiquitin is required for ATP-dependent, nonlysosomal intracellular protein degradation of abnormal proteins and normal proteins with a rapid turnover. Ubiquitin is covalently bound to proteins to be degraded, and presumably labels these proteins for degradation. Ubiquitin also binds to histone H2A in actively transcribed regions but does not cause histone H2A degradation, suggesting that ubiquitin is also involved in regulation of gene expression. Aberrant forms of this protein has been noticed in patients with Alzheimer's and Down syndrome. Nucleolin (NCL), a nucleolar phosphoprotein, is involved in the synthesis and maturation of ribosomes. It is located mainly in dense fibrillar regions of the nucleolus. Outer dense fiber of sperm tails 1 (Odf1). The outer dense fibers are cytoskeletal structures that surround the axoneme in the middle piece and principal piece of the sperm tail. The fibers function in maintaining the elastic structure and recoil of the sperm tail as well as in protecting the tail from shear forces during epididymal transport and ejaculation. Defects in the outer dense fibers lead to abnormal sperm morphology and infertility. Perilipin coats lipid storage droplets in fat cells (adipocytes), thereby protecting them until they can be broken down by hormone-sensitive lipase. Perilipin is the major cAMP-dependent protein kinase substrate in adipocytes and, when unphosphorylated, may play a role in the inhibition of lipolysis.