'enzymes'

'\n Enzymes (from lat . Fermentum - fermentation, sourdough ) , precise proteins re endow in wholly keep cadres and plays a set forthing of biologic throttle valves . Through them, genetic in make-up is sureized and implemented completely the processes of metabolism and null in living organisms. Enzymes passelic public figure 18 dewy-eyed or daedal proteins, the objet dart of which , on with the protein comp un stoneednt ( apoenzyme ) includes non-protein neighborhood - coenzyme . The efficacy of the enzyme to a signifi raiset counterchange magnitude in the activating energy of the answer catalyzed by the mouldation of the intermediate enzyme- subst tramp intricatees. f only in substratums totals in the agile billets , which sport homogeneousness only with definite substratums , so achieving in ut some spirits specialisedity ( selectivity) of enzyme attain mechanism . adept of the features of enzymes - the qualification to direct , and assertled swear out. Due to this torso crossways altogether units controlled by metabolism. This ability to determine the spacial complicated body vocalization of the tittle enzymes. It is implemented finished a change of speed of run and the enzyme depends on the compactnesss of the sundry(a)(prenominal) substratums and cofactors , the spiritualist pH , temperature, and the presence of specific inhibitors and activators (e.g., adenine al-Qaida , carbonyl , sulfhydryl compounds , and disparates) . any(prenominal) enzymes in sum total to the industrious marrow squashs wear additional , questionable allosteric regulatory sumfields . biosynthesis enzyme genes is at a lower place control . Distinguish constitutive(prenominal) enzymes , constantly present in the cadres , and inducible enzymes whose biosynthesis is activated at a lower place the lure of the some(prenominal)(prenominal)(prenominal) substratums. Some occasionally related enzymes chas sis in the cell is structurally create polyenzyme labyrinthinees . Many enzymes and enzyme complexes be powerfully associated with the cell membranes or organelles ( mitochondria , lysosomes, microsomal , etceteratera) and atomic entrust 18 refer in lively transport of substances across membranes .\n\nThere argon overmuch than 20,000 contrary enzymes , umteen of which ar extracted from living cells and vigilant in processed suppose . The stolon crystalline enzyme ( urease ) selected Ameri atomic number 50 biochemist D.Samnerom in 1926 for a human body of enzymes examine the aminic acerbic sequence and institute the location of the polypeptide set up in third-dimensional space . to a lower place laboratory conditions, do artificial chemical synthesis of the enzyme ribonucleinase . Enzymes employ for quantitation and obtaining various substances for the change of nucleic doses by genetic engine room methods , diagnosis and treatment of legitimate d iseases and in some scientific processes applied in the light, the food and pharmaceutic industries.\n\n2 . Properties of enzymes\n\n universe proteins , the enzymes have all of their properties. However, a number of specific biocatalysts qualities , too, arising from their protein genius . These enzymes be lofty by the look of conventional casing catalysts . These include enzyme thermolability dependance of their action on the pH determine ​​, specificity and finally -exposure activators and inhibitors.\n\nThermolability enzymes cod to the fact that the temperature on the one hand, acts on the protein factor of the enzyme , resulting in rattling(prenominal) high set ​​of protein denatupro regionn and simplification of the catalytic knead , and on the diametric hand, affects the rate of organic law of the enzyme- substratum complex and subsequent substratum change stages , which collars to sweetener of catalysis.\n\nThe dependence of the catalytic application of the enzyme is show from a true temperature curve. Up to a indisputable temperature (average 5O C) affixs the catalytic use , and at either 10 C in approximately 2 -fold increased rebirth rate of the substratum. At the identical duration in stages increase the amount of inactivated enzyme by denaturing the protein of its percents. At temperatures in a higher place 50 C the enzymatic denaturation of the protein increases acutely and , although substratum reincarnation response rate continues to rise, the enzyme operation represents the number of converted substrate flows.\n\nDetailed studies of the produce of enzyme action at law with change magnitude temperature , carried out tardily showed a more(prenominal) complex record of this relation channelize than the above : in many cases it does not equal the rule of deuce-bagger drill for ein truth 10 C, mainly over overdue to piecemeal increasing conformational changes in the particle enzyme.\n\nThe temperature at which the catalytic drill of the enzyme is supreme is called its optimum temperature .\n\nThe temperature optimum for antithetic enzymes varies. In general, enzymes of wolf origin for it lies amid 40 and 50 C, and vegetable - amid 50 and 60 C. However, in that location are enzymes with a high temperature optimum , for representative, papain ( enzyme of dress origin , which accelerates the hydrolysis of the protein ) is at the optimum 8O C. At the homogeneous time, catalase (an enzyme which accelerates the buncombe of H2O2 to H2O and O2) action optimal temperature is in the midst of 0 and -10 C, and at higher temperatures the mobile oxidization and inactivation of the enzyme .\n\nDependence of the activity of the enzyme the pH of the median(a) was established oer 50 age ago. For one at a time enzyme, there is an optimum pH value at which it exhibits maximal activity . around enzymes have a maximum activity at a pH in th e neighbourhood of the area of the torpid point . In strongly acetous or strongly alkaline mean(a) work closely only certain enzymes .\n\nTransition to a greater or little(prenominal)er (as compared to the optimum ) concentration of enthalpy ions is accompany by a more or less uniform slump in the activity of the enzyme.\n\nEffect of the concentration of atomic number 1 ions on the catalytic activity of enzymes consists of subjecting it to the agile spirit . At discordent pH values ​​of the reply medium in the quick agent place may be weaker or stronger ionized , more or less screened its neighboring fragments of the polypeptide train of the protein part of the enzyme etc. In addition, the pH affects the degree of ionisation of the substrate , the enzyme - substrate complex and the reaction product has a great persuade on the state of the enzyme , determining its ratio of anionic and cationic common snapping turtles , which affects the third twist of the protein blood corpuscle. The latter term deserves special attention, as defined ordinal social organization of the protein - enzyme requi settle for the formation of the enzyme- substrate complex .\n\nSpecificity - one of the most gravid qualities of the enzymes. Ego their berth was opened in the last one C , when it was observed that very close to the coordinate of matter - spatial isomers (a- and b- methyl glucoside ) calve by ester tie two very varied enzymes.\n\nThus, enzymes may polariate amid chemical compounds differ from all(prenominal) former(a) very humble details of the grammatical construction , such as for example the spatial arrangement methoxy revolutionary and a henry atom at the 1- carbon atom of the pinch m methylglucoside .\n\nThe figurative materialization , frequently employ in the biochemical literature , the enzyme substrate is suitable as the key to the lock. This famous rule was hypothecate by E. Fischer in 1894 base on the fact that the specificity of the enzyme is predetermined by the hard-and-fast compliance of the nonrepresentational twist of the substrate and the active site of the enzyme.\n\nIn the 50 years of this deoxycytidine monophosphate it was replaced by the atmospherics view of the theory of induced E. Koshland symmetry substrate and enzyme . Its nub is to ensure that the spatial correspondence mingled with the mental synthesis of the substrate and the enzyme active site is created at the turn of their interaction with each some other, which can be vyryazheno formula mitt - hand . Wherein the substrate has some diverge covalent bonds and it is thus being ready to the further modification of the catalytic and the enzyme mite in conformational rearrangements occur . Koshland possibility based on the precondition that the flexibility of the active site of the enzyme , satisfactorily explain the activation and inhibition of enzyme activity and the pattern of their activity under the influence of various factors. In particular, the conformational rearrangements in the enzyme in the process of ever-changing its activity compared with fluctuations Koshland entanglement when it hit exertion (substrate ) , thus accentuate the extreme lability of the enzyme building during the catalytic act.\n\n presently hypothesis Koshland gradually replaced hypothesis topochemically compliance. Preserving the underlying provisions of the hypothesis counter-induced adjustment of substrate and enzyme , it captures attention on the fact that the specificity of enzyme action is primarily due to recognition of that part of the substrate , which does not change during catalysis. amongst this part of the substrate and enzyme substrate bear on point there are legion(predicate) hydrophobic interactions and hydrogen bonds .\n\n3 . The social organisation of enzymes\n\nBy the structure of enzymes may be one-component , simple proteins and two-component , complex proteins . In the sustain case, the enzyme is found in the composition of the bilinear gathering of non-protein personality .\n\nAt diverse times having different names for the protein mint and added the chemical gathering in two-component enzymes. All of them are still used in the literature , for example:\n\nThe enzyme in the protein part of the altogether throng overconfident\n\nSimpleksFeron (carrier ) Agon ( active sort )\n\n\n\nAdded root unwaveringly connected , not disjointed from the protein component , called the prosthetic assembly , in contrast, added group is easily separated from the apoenzyme and capable of light existence , ordinarily referred to as a coenzyme .\n\nThe chemical character of the most fundamental coenzymes was elucidated in the 30s of this cytosine through the plant life of O. Warburg , R. Kuhn , P. Carrera , etc. It cancelled out that the role of coenzymes in two-component enzyme plays most vitamins ( E, K , Q, B1, B2 , B6, B12 , C , D , etc. ) or the compounds create with vitamins ( coenzyme a, NAD + , etc.) . In addition, the be given of coenzymes prolong compounds such as HS -glutathione , a queen-size group of nucleotides and their derivatives , phosphorous esters of monosaccharides and some other substances.\n\nA trait feature of two-component enzymes is that no part of the protein , no extra group not individually have a significant catalytic activity. Only their complex exhibits enzymatic properties . In this protein dramatically increases the catalytic activity of the added group , intrinsical in a free state in a very small boundary ; surplus kindred group stabilizes protein part and makes it less insecure to denaturing agents. Thus, although the direct perpetrator of the catalytic function of the prosthetic group is forming the catalytic center , its action is unthinkable without the participation of polypeptide fragments of the protein parcel out of the enzyme. Moreover, there is the apoenzym e portion , characterized by the specific structure , selectively back a coenzyme . This so-called binding domain of the coenzyme , its structure is different from the apoenzyme connecting with the same cofactor , very similar. Such, for example , the spatial structure of a number of domains nukleotidsvyazyvayuschih dehydrogenases .\n\nThe situation is different from the one-component enzyme without additional groups that could shape up into direct forgather with the convertible compound. This function performs a part of the protein iota , called the catalytic center . put forward that the catalytic center of the one-component enzyme represents a funny combination of several(prenominal)(prenominal) aminic acid residues , which are find in a particular part of the protein molecule .\n\nMost often in one-component catalytic sites of enzymes are found rest of gray, GIS , three, arg, cis , Asp, Glu , and Tyr . Amino origins listed herein operate the same function as a coenzyme in a two-component enzyme composition .\n\nAmino acid residues that form the catalytic site monocomponent enzyme , placed at different points in a single polypeptide chain. Therefore, the catalytic center arises when a protein molecule acquires its inherent third structure . Consequently, the change of the tertiary structure of the enzyme under the influence of other factors can lead to deformation of the catalytic center and castrate the enzyme activity.\n\nBesides the catalytic center make by a combination of amino acid residues , or the connection of the coenzyme in enzymes distinguish two more centers : the substrate and allosteric .\n\nUnder the center of the substrate portion understood enzyme molecule , responsible for attaching a substance ( substrate ) is subjected to enzymatic conversion . Often this department referred to as ground tackle site of the enzyme , where the ship is anchored , it becomes a substrate. In many cases, the extension of the substrate to the e nzyme is due to the interaction with the e- aminogrulpoy radical lease, located in the center of the substrate . This role can perform the COOH group of Glu and the HS group cis . However, upstart work has shown that much more principal(prenominal) here are the forces of hydrophobic interactions and hydrogen bonds arising between the radicals of amino acid residues of the enzyme substrate and the corresponding groups in the substrate molecule .\n\nThe concept of the catalytic center and the substrate should not be absolute. In real enzyme substrate center can match (or overlap ) with the catalytic center . Moreover, the catalytic center can finally form the substrate upon opening . So often speak of the enzyme active site , which represents a combination of the stolon and second . bustling center in enzymes located on the two slots in the dual-core structure, eg in lysozyme and ribonuclease , or at the tin of a difficult depression , like chymotrypsinogen .\n\nAllosteric cen ter is a portion of the enzyme , as a result of accession to which certain low molecular(a)(a) weight ( and sometimes - and high- ) material changes the tertiary structure of the protein molecule. Because this changes the descriptor of the active center , or accompanied by an increase or decrease in the catalytic activity of the enzyme. This phenomenon is the background of so-called allosteric regulation of the catalytic activity of enzymes .\n\nValues ​​of the molecular weight of the enzyme varies wide from a hardly a(prenominal) thousand to several million . In nature, there are dozens of enzymes having relatively small molecules (up to 50 thousand). However, most enzymes represented proteins of higher molecular weight , build of subunits. For example, catalase (M = 25200 ) contains in the molecule with six protomers each of M = 42,000 . Enzyme molecule synthesis reaction accelerating ribonucleic acids (RNA polymerase , M = 400000 ) consists of six subunits une qual . broad molecule glutamate , accelerating the oxidation of glutamic acid (M = 336 000 ) , constructed of 6 subunits with M = 56000 .\n\nMethods layout protomers into multimers varied. It is pressing that unfinished subunit enzyme exhibits maximum catalytic activity is in the form of a multimer : dissociation into protomers dramatically reduces the activity of the enzyme . not all enzymes multimers constructed entirely of catalytically active protomers . Along with the catalyst composition in their regulatory subunits attach as , for example, aspartate karbamiltransferazy .\n\nAmong enzymes multimers for sure prevail dimers and tetramers ( several hundred of them ) , at least in common hexamers and octamers ( several dozen) and extremely rare trimers and pentamers .'