Misplaced Pages

#552447

57-450: Miso is a traditional Japanese seasoning. MISO or Miso may also refer to: Miso Typically, miso is salty, but its flavor and aroma depend on the ingredients and fermentation process. Different varieties of miso have been variously described as salty, sweet, earthy, fruity, or savory . The origin of miso of Japan is not completely clear. In the Kamakura period (1185–1333),

114-412: A slippery sequence in the mRNA that codes for the polypeptide causes ribosomal frameshifting , leading to two different lengths of peptidic chains ( a and ab ) at an approximately fixed ratio. Many proteins and hormones are synthesized in the form of their precursors - zymogens , proenzymes , and prehormones . These proteins are cleaved to form their final active structures. Insulin , for example,

171-521: A ubiquitin -dependent process that targets unwanted proteins to proteasome . The autophagy -lysosomal pathway is normally a non-selective process, but it may become selective upon starvation whereby proteins with peptide sequence KFERQ or similar are selectively broken down. The lysosome contains a large number of proteases such as cathepsins . The ubiquitin-mediated process is selective. Proteins marked for degradation are covalently linked to ubiquitin. Many molecules of ubiquitin may be linked in tandem to

228-411: A cascade of sequential proteolytic activation of many specific proteases, resulting in blood coagulation. The complement system of the immune response also involves a complex sequential proteolytic activation and interaction that result in an attack on invading pathogens. Protein degradation may take place intracellularly or extracellularly. In digestion of food, digestive enzymes may be released into

285-566: A common meal was made up of a bowl of rice, some dried fish, a serving of miso, and a fresh vegetable. Until the Muromachi period (1337 to 1573), miso was made without grinding the soybeans, somewhat like nattō . In the Muromachi era, Buddhist monks discovered that soybeans could be ground into a paste, spawning new methods using miso to flavor other foods. In medieval times, the word temaemiso , meaning homemade miso, appeared. Miso production

342-406: A higher content of proteolytic enzymes. To create optimal conditions for enzymatic production and the growth of A. oryzae , the koji's environment must be carefully regulated. Temperature, humidity, and oxygen content are all important factors in maximizing mold growth and enzyme production and preventing other harmful bacteria from producing. Once the koji has reached a desirable flavor profile, it

399-425: A particular miso's flavor include temperature, fermentation duration, salt content, variety of kōji , and fermenting vessel. The most common flavor categories of miso are: Although white and red ( shiromiso and akamiso ) are the most common misos available, different varieties may be preferred in particular regions of Japan. In the eastern Kantō region that includes Tokyo, the darker brownish akamiso

456-503: A positively charged residue ( arginine and lysine ); chymotrypsin cleaves the bond after an aromatic residue ( phenylalanine , tyrosine , and tryptophan ); elastase cleaves the bond after a small non-polar residue such as alanine or glycine. In order to prevent inappropriate or premature activation of the digestive enzymes (they may, for example, trigger pancreatic self-digestion causing pancreatitis ), these enzymes are secreted as inactive zymogen. The precursor of pepsin , pepsinogen ,

513-506: A protein destined for degradation. The polyubiquinated protein is targeted to an ATP-dependent protease complex, the proteasome. The ubiquitin is released and reused, while the targeted protein is degraded. Different proteins are degraded at different rates. Abnormal proteins are quickly degraded, whereas the rate of degradation of normal proteins may vary widely depending on their functions. Enzymes at important metabolic control points may be degraded much faster than those enzymes whose activity

570-416: A protein, and proteins with segments rich in proline , glutamic acid , serine , and threonine (the so-called PEST proteins ) have short half-life. Other factors suspected to affect degradation rate include the rate deamination of glutamine and asparagine and oxidation of cystein , histidine , and methionine, the absence of stabilizing ligands, the presence of attached carbohydrate or phosphate groups,

627-476: A sweet, thick miso glaze, such as mochi and dango . Miso-glazed treats are strongly associated with Japanese festivals , although they are available year-round at supermarkets. The consistency of miso glaze ranges from thick and taffy -like to thin and drippy. Soybean miso is used to make a type of pickle called misozuke . These pickles are typically made from cucumber , daikon , napa cabbage , or eggplant , and are sweeter and less salty than

SECTION 10

#1732852091553

684-399: A ubiquitin-mediated proteolytic pathway. Caspases are an important group of proteases involved in apoptosis or programmed cell death . The precursors of caspase, procaspase, may be activated by proteolysis through its association with a protein complex that forms apoptosome , or by granzyme B , or via the death receptor pathways. Autoproteolysis takes place in some proteins, whereby

741-428: Is a traditional farmhouse variety made for personal use. Often called "rural miso", domestic barley is used more than imported barley. Containing glutamic acid and aromatic compounds such as ferulic acid and vanillic acid , barley miso is distinguished by a characteristic flavor. Miso's unique properties and flavor profile can be attributed to the compounds produced through the fermentation process. Miso, depending on

798-556: Is difficult to classify but is commonly done by grain type, color, taste, and background. Many regions have their own specific variation on the miso standard. For example, the soybeans used in Sendai miso are much more coarsely mashed than in normal soy miso. Miso made with rice such as shinshu miso ( 信州味噌 ) and shiro miso ( 白味噌 ) are called kome miso ( 米味噌 ). Miso's taste, aroma, texture, and appearance vary by region and season. Other important variables that contribute to

855-410: Is isolated from plant matter (usually rice) and cultivated. In the past, the natural presence of A. oryzae spores was relied upon to create koji, but because of the difficulty of producing the culture, tane-kōji is added almost exclusively in both industrial and traditional production of miso. Tane-kōji is produced much in the same way as koji, but also has a small portion of wood ash added to

912-401: Is largely constant under all physiological conditions. One of the most rapidly degraded proteins is ornithine decarboxylase , which has a half-life of 11 minutes. In contrast, other proteins like actin and myosin have a half-life of a month or more, while, in essence, haemoglobin lasts for the entire life-time of an erythrocyte . The N-end rule may partially determine the half-life of

969-575: Is left intact. Certain chemicals cause proteolysis only after specific residues, and these can be used to selectively break down a protein into smaller polypeptides for laboratory analysis. For example, cyanogen bromide cleaves the peptide bond after a methionine . Similar methods may be used to specifically cleave tryptophanyl , aspartyl , cysteinyl , and asparaginyl peptide bonds. Acids such as trifluoroacetic acid and formic acid may be used for cleavage. Like other biomolecules, proteins can also be broken down by high heat alone. At 250 °C,

1026-399: Is necessary to break down proteins into small peptides (tripeptides and dipeptides) and amino acids so they can be absorbed by the intestines, and the absorbed tripeptides and dipeptides are also further broken into amino acids intracellularly before they enter the bloodstream. Different enzymes have different specificity for their substrate; trypsin, for example, cleaves the peptide bond after

1083-564: Is popular while in the western Kansai region encompassing Osaka , Kyoto , and Kobe , the lighter shiromiso is preferred. A more nuanced breakdown of the flavors is as follows: The distinct and unique aroma of miso determines its quality. Many reactions occur among the components of miso, primarily the Maillard reaction, a non-enzymatic reaction of an amino group with a reducing sugar. The volatile compounds produced from this reaction give miso its characteristic flavor and aroma. Depending on

1140-700: Is produced industrially in large quantities, and traditional homemade miso has become a rarity. In recent years, many new types of miso have appeared, including ones with added soup stocks or calcium, made with beans other than soy, or having reduced salt for health, among other varieties available. The ingredients used to produce miso may include any mix of soybeans , barley, rice, buckwheat , millet , rye , wheat, hemp seed, and cycad , among others. Lately, producers in other countries have also begun selling miso made from chickpeas, corn, azuki beans , amaranth , and quinoa . Fermentation time ranges from as little as five days to several years. The variety of Japanese miso

1197-524: Is relatively simple, so homemade versions spread throughout Japan. Miso was used as military provisions during the Sengoku period , and making miso was an important economic activity for daimyō s of that era. During the Edo period (1603–1868), miso was also called hishio ( 醤 ) and kuki ( 豆支 ) and various types of miso that fit with each local climate and culture emerged throughout Japan. Today, miso

SECTION 20

#1732852091553

1254-419: Is secreted by the stomach, and is activated only in the acidic environment found in stomach. The pancreas secretes the precursors of a number of proteases such as trypsin and chymotrypsin . The zymogen of trypsin is trypsinogen , which is activated by a very specific protease, enterokinase , secreted by the mucosa of the duodenum . The trypsin, once activated, can also cleave other trypsinogens as well as

1311-490: Is synthesized as preproinsulin , which yields proinsulin after the signal peptide has been cleaved. The proinsulin is then cleaved at two positions to yield two polypeptide chains linked by two disulfide bonds . Removal of two C-terminal residues from the B-chain then yields the mature insulin. Protein folding occurs in the single-chain proinsulin form which facilitates formation of the ultimate inter-peptide disulfide bonds, and

1368-414: Is the basis of a traditional Japanese breakfast. Miso is used in many other types of soup and soup-like dishes, including some kinds of ramen , udon , nabe , and imoni . Generally, such dishes have the title miso prefixed to their name (for example, miso-udon ) and have a heavier, earthier flavor and aroma than other Japanese soups that are not miso-based. Many traditional confections use

1425-435: Is the breakdown of proteins into smaller polypeptides or amino acids . Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called proteases , but may also occur by intra-molecular digestion. Proteolysis in organisms serves many purposes; for example, digestive enzymes break down proteins in food to provide amino acids for

1482-511: Is usually mixed with salt to prevent further fermentation. Although other strains of fungi have been used to produce koji, A. oryzae is the most desirable because of several properties, including the fact that it does not produce aflatoxin . Miso typically comes as a paste in a sealed container requiring refrigeration after opening. Natural miso is a living food containing many beneficial microorganisms such as Tetragenococcus halophilus , which can be killed by overcooking. For this reason,

1539-456: Is very important for the sensory evaluation of the aroma of rice miso. The unique sensory properties of miso are complex. The key factor in the final product's overall quality is the microorganisms' enzymatic activity. They use the composition of miso (rice, barley, and soybeans) to produce different pigments, flavors, and aroma compounds. Proteolysis of soybean protein produces constituent amino acids that impart an umami taste that enhances

1596-454: The peptide bond is cleaved in a self-catalyzed intramolecular reaction . Unlike zymogens , these autoproteolytic proteins participate in a "single turnover" reaction and do not catalyze further reactions post-cleavage. Examples include cleavage of the Asp-Pro bond in a subset of von Willebrand factor type D (VWD) domains and Neisseria meningitidis FrpC self-processing domain, cleavage of

1653-598: The Asn-Pro bond in Salmonella FlhB protein, Yersinia YscU protein, as well as cleavage of the Gly-Ser bond in a subset of sea urchin sperm protein, enterokinase, and agrin (SEA) domains. In some cases, the autoproteolytic cleavage is promoted by conformational strain of the peptide bond. Abnormal proteolytic activity is associated with many diseases. In pancreatitis , leakage of proteases and their premature activation in

1710-433: The breakdown of proteins into smaller peptides or amino acids. These both aid in the enzymatic digestion of rice and soybeans. Depending on the strain of A. oryzae , the enzymatic composition varies, thereby changing the characteristics of the final miso product. For example, the strain used to create the sweeter white miso would likely produce a higher content of amylolytic enzymes, while comparatively, soybean miso might have

1767-488: The breaking down of connective tissues in the lung. Other proteases and their inhibitors may also be involved in this disease, for example matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Other diseases linked to aberrant proteolysis include muscular dystrophy , degenerative skin disorders, respiratory and gastrointestinal diseases, and malignancy . Protein backbones are very stable in water at neutral pH and room temperature, although

Miso (disambiguation) - Misplaced Pages Continue

1824-538: The environment for extracellular digestion whereby proteolytic cleavage breaks proteins into smaller peptides and amino acids so that they may be absorbed and used. In animals the food may be processed extracellularly in specialized organs or guts , but in many bacteria the food may be internalized via phagocytosis . Microbial degradation of protein in the environment can be regulated by nutrient availability. For example, limitation for major elements in proteins (carbon, nitrogen, and sulfur) induces proteolytic activity in

1881-547: The final functional form of protein is termed proprotein , and these proproteins may be first synthesized as preproprotein. For example, albumin is first synthesized as preproalbumin and contains an uncleaved signal peptide. This forms the proalbumin after the signal peptide is cleaved, and a further processing to remove the N-terminal 6-residue propeptide yields the mature form of the protein. The initiating methionine (and, in bacteria, fMet ) may be removed during translation of

1938-546: The fungus Neurospora crassa as well as in of soil organism communities. Proteins in cells are broken into amino acids. This intracellular degradation of protein serves multiple functions: It removes damaged and abnormal proteins and prevents their accumulation. It also serves to regulate cellular processes by removing enzymes and regulatory proteins that are no longer needed. The amino acids may then be reused for protein synthesis. The intracellular degradation of protein may be achieved in two ways—proteolysis in lysosome , or

1995-579: The generation and ineffective removal of peptides that aggregate in cells. Proteases may be regulated by antiproteases or protease inhibitors , and imbalance between proteases and antiproteases can result in diseases, for example, in the destruction of lung tissues in emphysema brought on by smoking tobacco. Smoking is thought to increase the neutrophils and macrophages in the lung which release excessive amount of proteolytic enzymes such as elastase , such that they can no longer be inhibited by serpins such as α 1 -antitrypsin , thereby resulting in

2052-453: The laboratory, and it may also be used in industry, for example in food processing and stain removal. Limited proteolysis of a polypeptide during or after translation in protein synthesis often occurs for many proteins. This may involve removal of the N-terminal methionine , signal peptide , and/or the conversion of an inactive or non-functional protein to an active one. The precursor to

2109-416: The microorganism in combination with the variety of soybean or cereal used, many flavor compounds are produced that give rise to the different types of miso. Fermentation products such as furanone compounds, including 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone (HEMF) and 4-hydroxy-2,5 dimethyl-3(2H)-furanone (HDMF) are novel flavor compounds of miso. HEMF is especially known for its sweet aroma and

2166-471: The miso should be added to soups or other foods prepared just before they are removed from the heat. Using miso without any cooking may be even better. Miso is a part of many Japanese-style meals. It most commonly appears as the main ingredient of miso soup , which is eaten daily by much of the Japanese population. The pairing of plain rice and miso soup is a fundamental unit of Japanese cuisine . This pairing

2223-442: The mixture which gives important nutrients to the fungus as well as promoting sporulation . A. oryzae is an aerobic fungus and is the most active fermenting agent in koji as it produces amylolytic , and proteolytic enzymes which are essential to creating the final miso product. Amylolytic enzymes such as amylase aid in the breakdown of starch in the grains to sugar and dextrin, while proteolytic enzymes such as protease catalyze

2280-483: The nascent protein. For E. coli , fMet is efficiently removed if the second residue is small and uncharged, but not if the second residue is bulky and charged. In both prokaryotes and eukaryotes , the exposed N-terminal residue may determine the half-life of the protein according to the N-end rule . Proteins that are to be targeted to a particular organelle or for secretion have an N-terminal signal peptide that directs

2337-414: The organism, such as its hormonal state as well as nutritional status. In time of starvation, the rate of protein degradation increases. In human digestion , proteins in food are broken down into smaller peptide chains by digestive enzymes such as pepsin , trypsin , chymotrypsin , and elastase , and into amino acids by various enzymes such as carboxypeptidase , aminopeptidase , and dipeptidase . It

Miso (disambiguation) - Misplaced Pages Continue

2394-489: The organism, while proteolytic processing of a polypeptide chain after its synthesis may be necessary for the production of an active protein. It is also important in the regulation of some physiological and cellular processes including apoptosis , as well as preventing the accumulation of unwanted or misfolded proteins in cells. Consequently, abnormality in the regulation of proteolysis can cause disease. Proteolysis can also be used as an analytical tool for studying proteins in

2451-467: The pancreas results in the self-digestion of the pancreas . People with diabetes mellitus may have increased lysosomal activity and the degradation of some proteins can increase significantly. Chronic inflammatory diseases such as rheumatoid arthritis may involve the release of lysosomal enzymes into extracellular space that break down surrounding tissues. Abnormal proteolysis may result in many age-related neurological diseases such as Alzheimer 's due to

2508-425: The peptide bond may be easily hydrolyzed, with its half-life dropping to about a minute. Protein may also be broken down without hydrolysis through pyrolysis ; small heterocyclic compounds may start to form upon degradation. Above 500 °C, polycyclic aromatic hydrocarbons may also form, which is of interest in the study of generation of carcinogens in tobacco smoke and cooking at high heat. Proteolysis

2565-461: The peptide bonds in a protein ( acid hydrolysis ). The standard way to hydrolyze a protein or peptide into its constituent amino acids for analysis is to heat it to 105 °C for around 24 hours in 6M hydrochloric acid . However, some proteins are resistant to acid hydrolysis. One well-known example is ribonuclease A , which can be purified by treating crude extracts with hot sulfuric acid so that other proteins become degraded while ribonuclease A

2622-417: The precursors of other proteases such as chymotrypsin and carboxypeptidase to activate them. In bacteria, a similar strategy of employing an inactive zymogen or prezymogen is used. Subtilisin , which is produced by Bacillus subtilis , is produced as preprosubtilisin, and is released only if the signal peptide is cleaved and autocatalytic proteolytic activation has occurred. Proteolysis is also involved in

2679-408: The presence of free α-amino group, the negative charge of protein, and the flexibility and stability of the protein. Proteins with larger degrees of intrinsic disorder also tend to have short cellular half-life, with disordered segments having been proposed to facilitate efficient initiation of degradation by the proteasome . The rate of proteolysis may also depend on the physiological state of

2736-448: The protein products of proto-oncogenes, which play central roles in the regulation of cell growth. Cyclins are a group of proteins that activate kinases involved in cell division. The degradation of cyclins is the key step that governs the exit from mitosis and progress into the next cell cycle . Cyclins accumulate in the course the cell cycle, then abruptly disappear just before the anaphase of mitosis. The cyclins are removed via

2793-546: The protein to its final destination. This signal peptide is removed by proteolysis after their transport through a membrane . Some proteins and most eukaryotic polypeptide hormones are synthesized as a large precursor polypeptide known as a polyprotein that requires proteolytic cleavage into individual smaller polypeptide chains. The polyprotein pro-opiomelanocortin (POMC) contains many polypeptide hormones. The cleavage pattern of POMC, however, may vary between different tissues, yielding different sets of polypeptide hormones from

2850-475: The rate of hydrolysis of different peptide bonds can vary. The half life of a peptide bond under normal conditions can range from 7 years to 350 years, even higher for peptides protected by modified terminus or within the protein interior. The rate of hydrolysis however can be significantly increased by extremes of pH and heat. Spontaneous cleavage of proteins may also involve catalysis by zinc on serine and threonine. Strong mineral acids can readily hydrolyse

2907-449: The regulation of many cellular processes by activating or deactivating enzymes, transcription factors, and receptors, for example in the biosynthesis of cholesterol, or the mediation of thrombin signalling through protease-activated receptors . Some enzymes at important metabolic control points such as ornithine decarboxylase is regulated entirely by its rate of synthesis and its rate of degradation. Other rapidly degraded proteins include

SECTION 50

#1732852091553

2964-426: The relatively dull taste of soybean by itself. Soy protein contains a substantial amount of glutamate , the salt of which is known as MSG or monosodium glutamate , a popular ingredient used by food manufacturers to improve the taste of their products. The umami effect of MSG itself is one-dimensional. The umami taste of miso is multidimensional because of the myriad amino acids and fermentation products. Barley miso

3021-452: The same polyprotein. Many viruses also produce their proteins initially as a single polypeptide chain that were translated from a polycistronic mRNA. This polypeptide is subsequently cleaved into individual polypeptide chains. Common names for the polyprotein include gag ( group-specific antigen ) in retroviruses and ORF1ab in Nidovirales . The latter name refers to the fact that

3078-633: The standard Japanese salt pickle . Other foods with miso as an ingredient include: Claims that miso is high in vitamin B 12 have been contradicted in some studies. Some experts suggest that miso is a source of Lactobacillus acidophilus . Miso is relatively high in salt which could contribute to increased blood pressure in the small percentage of the population with sodium-sensitive prehypertension or hypertension . Several studies using salt-sensitive hypertensive models and analyzing long-term intake have suggested that miso lessens salt's effects on blood pressure. Proteolysis Proteolysis

3135-445: The ultimate intra-peptide disulfide bond, found in the native structure of insulin. Proteases in particular are synthesized in the inactive form so that they may be safely stored in cells, and ready for release in sufficient quantity when required. This is to ensure that the protease is activated only in the correct location or context, as inappropriate activation of these proteases can be very destructive for an organism. Proteolysis of

3192-550: The variety, consists of a starter culture called kōji ( 麹 ), soybeans, and usually a grain (either rice, barley, or rye). The miso goes through a two-step process; first creating the kōji , and second the kōji is combined with the other components, and the mixture is left to be enzymatically digested, fermented and aged. Koji is produced by introducing the mold Aspergillus oryzae onto steamed white rice. This mold culture comes from dried A. oryzae spores called tane-kōji ( 種麹 , たねこうじ ) or "starter koji" and

3249-439: The zymogen yields an active protein; for example, when trypsinogen is cleaved to form trypsin , a slight rearrangement of the protein structure that completes the active site of the protease occurs, thereby activating the protein. Proteolysis can, therefore, be a method of regulating biological processes by turning inactive proteins into active ones. A good example is the blood clotting cascade whereby an initial event triggers

#552447