HYDROXYLATION OF STEROIDS.   Term Paper ID:23047 Click to get this paper

Essay Subject: Examines reaction required for synthesis & alteration of pharmacological potential & metabolic functioning.... More...

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Paper Abstract: Examines reaction required for synthesis & alteration of pharmacological potential & metabolic functioning. Paper Introduction: The Hydroxylation of Steroids Three major classes of steroids include sterols, steroid hormones, and bile acids. Perhaps the most important sterol, cholesterol, serves as the precursor of both steroid hormones and bile acids. The synthesis of these compounds requires hydroxylation reactions. In addition, steroid-like substances such as vitamin D also undergo hydroxylation reactions. Many of these reactions are performed by the cytochrome P450 superfamily of enzymes. The many different forms of cytochrome P450 oxidize a wide variety of substrates. Moreover, in recent years, it has become apparent that many of these reactions exhibit remarkable regio- or stereoselectivity. For the most part, hydroxylation serves to increase the polarity of the rather hydrophobic steroids. By increasing their aqueous solubility, the hydroxyl Text of the Paper: The entire text of the paper is shown below. However, the text is somewhat scrambled. We want to give you as much information as we possibly can about our papers and essays, but we cannot give them away for free. In the text below you will find that while disordered, many of the phrases are essentially intact. From this text you will be able to get a solid sense of the writing style, the concepts addressed, and the sources used in the research paper. ofthese compounds requires hydroxylation reactions In addition steroid-like recent years it has become apparentthat many Conversely oxidation may also facilitate the of these compounds may be compounds achieve their variousphysiologic effects The sterol cholesterol serves as the progestagens the glucocorticoids themineralocorticoids the androgens hormones havedistinctly different functions The first step in the carbon atoms Hence the synthesis of steroids ultimately form the keyintermediate in the synthesis of steroid hormones to a double bond The can produce theglucocorticoids the mineralocorticoids Theglucocorticoids promote gluconeogenesis and the formation of glycogen is thenhydroxylated again at C The subsequent oxidation of the Cl and HCO by the kidney This typically results testosterone loss of the C angularmethyl group This enzyme inserts oxygen into respectively Estrogens alsohave an important are synthesized by theadrenal cortex Last androgens and estrogens are transcortin and albumin Once thehormones metabolic enzymes in their respective target tissues manner and eventually stimulates uterinegrowth Hydroxylation into the and positions oxidation of C to fat-soluble vitamins One steroid-like substance that undergoes however does not have any the kidneys and further hydroxylated reactions require NADPH and O The water This sequence ofevents is similar to a superfamily of enzymeswhich have an absorption maximum at nanometers state andan oxidized ferric state during the transport compound which transfers oneelectron to the oxidized form of cytochrome oxidize a wide variety of substrates By making foreign compounds as drugs carcinogens and plant fact this characteristic can be used as a sensitive P IIB are responsible for catalyzing and In addition the enzyme is also responsible P reductase It is generally considered that thegreater concentration of i e peroxidases tyrosinases and unspecific monooxygenases the classic however remains incompletely understood Various inherited disorders to enlargement ofthe adrenal glands becomes apparent within severalmonths Yet another inherited enzyme can also cause high levels ofandrogens and piriforme have all beenshown to introduce Such compounds are potentially capable of Lactobacillus Peptostreptococcus Proprionibacterium and others During thus produced are then either reexcreted into the competitive inhibitors of ethinyl estradiol hydroxylation Moreover such and deoxycorticosterone acetylenicdeoxycorticosterone represent the an activated oxygen to the of oralcontraceptives is ethinylestradiol This compound undergoes hydroxylation methylation IIIA vary widely among individuals Moreover the enzymecan be induced are also used forvarious medical purposes For instance fungi have been used to achieve oic acid In addition to pharmacologic products microorganisms reactions are very important in steroidchemistry They are Withfurther scientific advances the cytochrome P enzymes of Lapenson D P Gillette J Gelboin H V of steroid hydroxylation reactions by high-performance liquid chromatography as indicator C Eaton D L Decreased microorganisms Journal of Basic Microbiology Guengerich F P P F Cytochrome P C scc One enzyme with recognition sites Biochemistry Hu S Molecular Biology Kubli-Garfias C Chemical structure Stryer L Biochemistry Second edition San Francisco CA W H and molecular biology results Journal of Steroid Biochemistry the most important sterol cholesterol serves asthe precursor of by the cytochrome P superfamily ofenzymes The many different forms thepolarity of the rather hydrophobic steroids By increasing for these reactions Steroid substances are alsoused compounds are forthe most part water insoluble Hence of eukaryotic membranes It gives rise to fivedifferent types all containthe four-ring structure of the sterol nucleus Despite thisstructural of cholesterol contains carbon atoms In contrast hydroxylated to give dihydroxycholesterol Then the bond between C and pregnenolone's hydroxyl group is oxidized to a keto In addition progesterone is also required for the maintenance of cortisol Initially hydroxypregnenolone andprogesterone become to copewith stress The synthesis of the mineralocorticoid aldosterone deoxycorticosterone corticosterone andthen to aldosterone The C side chain thengives the androgen androstenedione With further formation directly from androstenedione The formation of an The androgens and estrogensstimulate the development of male The progestagens for instance are produced physiologic events Asthey are generally hydrophobic the hormones are transcription factors Indeed through their effects hormone'saffinity for DNA The complex enters following steps saturation of the double bond epimerization of gallbladder The compounds then act as emulsifyingagents compound is then photolyzed by ultraviolet light topre-vitamin D Eventually kidneys In the liver hydroxylation of vitamin hormone to increaseserum Ca Steroid hydroxylation reactions of the O molecule's oxygen atoms goesinto the substrate and hydroxylation of steroids generally requires the activation ofoxygen This Cytochromeswere initially found to be involved in respiration In David chain flavoprotein The electrons are then transferred to anonheme is because their broad andoverlapping sensitivities for cytochrome P occur in liver These enzymes arecapable of hydroxylating Furthermore the reactions exhibit remarkable of the P IIfamily are exceptionally stereospecific and protein cytochrome P C scc determineswhether the to a C sex steroid The regulation of androgens in the testes andcortisol in the adrenal glands Although keto and oxepin tautomers as intermediates The glucocorticoids andmineralocorticoids there is an of the female fetus In males while the with hydroxylase deficiency hydroxylase deficiency certain microorganisms For example the fungi compound can then be transformed bya epoxide to a bacteria generally increases from the jejunum through theileum Substances which are reabsorbed are typicallytransported to the liver where can additionally be inhibited by variouscompounds For instance Purba et inactivation of cytochrome P can be accomplished by theacetylenic pseudo-substrates for the targeted enzymes Then it enzyme molecule The hydroxylation of steroids additionally has reaction is livermicrosomal cytochrome P IIIA also pharmacokinetics Increases in the compound's rate ofclearance could diminish structurallycomplex substrates to yield chiral products usually requires sophisticatedand Mycobacterium is used toperform a hydroxylation resulting in the could even be used in thefood industry to cytochrome P enzymes These proteins occur of different steroid compounds Literature Cited Aoyama T The Journal of Biological Chemistry December Arlotto M P Trant of catecholestrogens American Journal of Obstetrics and Gynecology Toxicology and Applied Pharmacology Groh and Gynecology Part December Guengerich F P Metabolism of ethynylestradiol P A Burnett V L Halpert J R Structural determinants Wright C L Holbert G W Behavior December Smith K E Ahmed F Antoniou Wiley Sons Zachmann M Defects in steroidogenic enzymes The Hydroxylation of Steroids Three major classes of steroids substances such as vitamin D also undergo of these reactions exhibit remarkable regio orstereoselectivity For urinary excretionof the compounds Many microorganisms are capable of steroidhydroxylation altered through hydroxylation Steroids such as cholesterol the steroid hormones the major steroid precursor Thiscompound which is derived from acetyl and the estrogens Thesehormones are all synthesis of steroid hormones is stimulated byadrenocorticotropic hormone initially requires the removal of a C sidechain First cholesterol's pregnenolone The transformation of pregnenolone hormone's primary function is to prepare thelining of the androgens or the estrogens Highly specific hydroxylations at C Inaddition they stimulate the degradation of fat and C angularmethyl group to an aldehyde ultimately gives in an increase inblood volume and blood pressure Hydroxyprogesterone and aromatic ring formation yield estradiol In contrast the C-H bonds of the C methyl during role in the ovarian cycle A number of formed by the gonads The steroid hormones provide complex have entered their target cells they bind to cytoplasmicreceptors As an example estradiol binds to a specific receptor in reactions are also involved in the conversion ofcholesterol a carboxylate and conjugation of this side chaincarboxylate with glycine hydroxylation reactions isvitamin D Initially cholesterol is biologicactivity Rather it must first be converted to an to yield theactive hormone dihydroxycholecalciferol Thishormone acts incorporated hydroxyl group's oxygen atom typically comes from the the hydroxylation of phenylalanine as follows when complexed withcarbon monoxide This superfamily known of a single electron NADPH transfers P The reduced form of theenzyme them activates O hydrophobiccompounds more water-soluble hydroxylation reactions facilitate theirurinary excretion products In addition to promoting urinary fingerprint for the identification of a specific hydroxylations of androgens respectively Similarly the conversion of for whether ornot the pathway this protein in the gonads as compared estrogen hydroxylase appears to be acytochrome P These of steroid hormone synthesis result fromhydroxylase deficiencies The most and elevated levels of androgens In females this cancause virilization deficiency hydroxylase deficiency interferes with the conversion of deoxycortisol to virilization In addition to various organs of a hydroxyl group at the position interacting with thecardiac glycoside receptors of heart muscle passage through theintestinal system sterols bile ortransported to the kidney substances as primaquine and tolbutamide actas noncompetitive first rationally designed enzyme-activated inhibitors of acetylenic bond it forms a transient reactive oxirene This and glucuronidation prior to being excreted In humans the by barbiturates and rifampicin Thus this potentialvariability in the glucocorticoid is typicallyadministered to reverse the symptoms chirality For example apatent has already been may also be employed in the agrochemical industry for involved in the different compounds' biosynthesis andthe excretion Typically variousmicroorganisms may one day be Waxman D J Gonzalez F J Sequence requirements of P identity and function Methods in Enzymology expression of cytochrome P mRNAs and related steroid hydroxylation activities Inhibition of oral contraceptive steroid metabolizing enzymes by two actions Hydroxylase and lyase Journal of Genain G Azerad R Microbial transformation of of corticosteroids and its relationship with their acute induction Freeman and Company Voet D Voet J and Molecular Biology June both steroid hormones and bile acids The synthesis of cytochrome P oxidize a widevariety of substrates Moreover in their aqueoussolubility the hydroxyl functionalities may make certain substancesbioactive to achieve a number of therapeutic objectives The pharmacologicpotential it is primarily through differenthydroxylation reactions that the of steroid hormones These include the followingcategories similarity however the various steroid the steroid hormones are comprised of less than C iscleaved by desmolase The three reactions group Second the compound's double bond is isomerized pregnancy From progesterone continued chemical transformations hydroxyprogesterone This compound subsequentlybecomes deoxycortisol and then cortisol requires thehydroxylation of progesterone at C This deoxycorticosterone mineralocorticoids increase reabsorption of Na reduction of the ketogroup testosterone is formed From aromaticring requires the enzyme aromatase and female secondary sex characteristicsand sexual behavior patterns by the corpus luteum Inaddition the glucocorticoids and mineralocorticoids transported in the bloodin combination with the glycoprotein on gene expression the steroid hormones induce thesynthesis of numerous the nucleus binds tothe DNA in a highly specific the OHgroup introduction of OH groups in the digestion and absorption of fats and pre-vitamin D spontaneously isomerizes togive vitamin D This compound D gives hydroxycholecalciferol This compoundis then transported to are mediated by monooxygenases ormixed-function oxygenases All of the the other is reduced to activation is typically achieved by Keilindiscovered that the proteins alternate between a reduced ferrous iron protein adrenodoxin It is this xenobiotic lipophilic substrates enable theenzymes to hundreds of structurally diverse low molecularweight lipophilic compounds including such regio or stereoselectivity for certainsubstrates In regioselective For instance P IIB and cholesterol substrate becomes a glucocorticoid or analdosterone these activities appears to be determinedby the availability of the hydroxylation of estrogens may involve three differenthydroxylating systems chemical mechanism which results in aromatic ring formation overproduction of adrenocorticotropichormone High levels of this substance generally lead sexual organs appearnormal at birth sexual precocity generally also causes adrenal enlargement Similarly hydroxylase deficiency Mucorgriseocyanus Actinomucor elegans and Thamnostylum hydroxy substituent found in cardioactivesteroids to the colon Important genera include Bacteroides Eubacterium Bifidobacterium Fusobacterium they undergo further metabolization Thecompounds al found that several drugs andsteroids act as steroids In fact the acetylenic analogs ofandrostenedione Plomestane has been hypothesized thatwhen the monooxygenase delivers various pharmacologicimplications For example the main estrogenic component known as P NF Levels ofcytochrome P its effectiveness In addition to estrogen other steroid hormones time-consuming chemical techniques More recently however steroid-transforming formation of hydroxy oxo-stigmast dien create flavors and essences Obviously hydroxylation in a diverse array of organisms Korzekwa K Nagata K Adesnik M Reiss A J M Estabrook R W Measurement Part December Chen Z White C H Schade K Horhold-Schubert C Steroid metabolism with intestinal in humans Life Sciences Hall of cytochrome P B specificity Evidence for five substrate Enzyme-activated inhibitors of steroidal hydroxylases Journal of Steroid Biochemistry and T Microbial transformations of steroids Biochemical Society Transactions November Discrepancies between clinical steroid research include sterols steroid hormones and bile acids Perhaps hydroxylation reactions Many of these reactions are performed the most part hydroxylation serves to increase In addition competitive noncompetitive and mechanism-based inhibitors exist and the bileacids serve a diverse range of functions These coenzyme A represents an integralcomponent somewhat similar in structure For example secretion in the anterior pituitary Thechemical structure C and C atoms are to progesterone involves twodifferent steps First the uterus for implantation of an ovum C and C produce theglucocorticoid protein and alsoinfluence different vital functions involving the body's ability aldosterone Thus progesterone is converted to can also be further oxidized to producedehydroisoandrosterone Cleavage of the another estrogen estrone is derived through aromatic ring the first two oxidative steps to producethe carboxyaldehyde derivative different organs produce the various steroid hormones chemicalsignalling systems for the coordination of various enter the nucleus and act as thecytoplasm of the uterine cell This binding increases the to bile acids This process involves the or taurine Once formed the bile acidsare secreted into the converted to dehydrocholesterol pro-vitamin D This active form byhydroxylation reactions in the liver and in a synergistic manner with parathyroid O rather than from H O One molecule RH O NADPH H ROH H O NADP The as the cytochromeP enzymes all possess a heme prosthetic group its high-potential electrons to an electron-transport Subsequent research has observed that cytochrome enzymes dominatehepatic metabolism This At least and perhaps as may as individualforms of excretion cytochrome P enzymeshydroxylations are also involved in biosynthesis type ofcytochrome P In particular many members progesterone to androstenedione requiresa C lyase This single proceeds to a C steroid such as cortisol or to theadrenal glands results in the production of reactions produce and arenoxides in equilibrium with common of these is hydroxylasedeficiency With diminished production of the external genitalia are masculinized duringdevelopment cortisol anddeoxycorticosterone to corticosterone As the body steroid hydroxylation canbe accomplished by of progesterone andsome other steroids This hydroxy Intestinal tract bacteria can also hydroxylate steroids Theconcentration of and steroids may be transformed reabsorbed orexcreted in feces for urinary excretion Steroid hydroxylation inhibitors of the reaction In addition mechanism-basedor suicide aromatase The compounds act as intermediate is then able tocovalently bind to the major catalyst for the hydroxylation rate of ethinylestradiol hydroxylation can affectthe contraceptive's of hydroxylase deficiency The regio and stereoselective transformation of taken for the fungal preparation ofanticholesterolemic compounds A strain of theproduction of herbicides and pesticides fungi the reactions are performed by employed to enhance the pharmacologicpotential for cytochrome P IIB catalytic activity Ball P Knuppen R Formation metabolism and physiologic importance in hepatic hyperplastic nodules in male F rats steroids and drugs American Journal of Obstetrics Steroid Biochemistry and Molecular Biology He Y Luo Z Klekota steroids Contribution to hydroxylations Steroids April Johnston J O of lordosis in the female rat Hormones and G Biochemistry New York NY John ofthese compounds requires hydroxylation reactions In addition steroid-like recent years it has become apparentthat many Conversely oxidation may also facilitate the of these compounds may be compounds achieve their variousphysiologic effects The sterol cholesterol serves as the progestagens the glucocorticoids themineralocorticoids the androgens hormones havedistinctly different functions The first step in the carbon atoms Hence the synthesis of steroids ultimately form the keyintermediate in the synthesis of steroid hormones to a double bond The can produce theglucocorticoids the mineralocorticoids Theglucocorticoids promote gluconeogenesis and the formation of glycogen is thenhydroxylated again at C The subsequent oxidation of the Cl and HCO by the kidney This typically results testosterone loss of the C angularmethyl group This enzyme inserts oxygen into respectively Estrogens alsohave an important are synthesized by theadrenal cortex Last androgens and estrogens are transcortin and albumin Once thehormones metabolic enzymes in their respective target tissues manner and eventually stimulates uterinegrowth Hydroxylation into the and positions oxidation of C to fat-soluble vitamins One steroid-like substance that undergoes however does not have any the kidneys and further hydroxylated reactions require NADPH and O The water This sequence ofevents is similar to a superfamily of enzymeswhich have an absorption maximum at nanometers state andan oxidized ferric state during the transport compound which transfers oneelectron to the oxidized form of cytochrome oxidize a wide variety of substrates By making foreign compounds as drugs carcinogens and plant fact this characteristic can be used as a sensitive P IIB are responsible for catalyzing and In addition the enzyme is also responsible P reductase It is generally considered that thegreater concentration of i e peroxidases tyrosinases and unspecific monooxygenases the classic however remains incompletely understood Various inherited disorders to enlargement ofthe adrenal glands becomes apparent within severalmonths Yet another inherited enzyme can also cause high levels ofandrogens and piriforme have all beenshown to introduce Such compounds are potentially capable of Lactobacillus Peptostreptococcus Proprionibacterium and others During thus produced are then either reexcreted into the competitive inhibitors of ethinyl estradiol hydroxylation Moreover such and deoxycorticosterone acetylenicdeoxycorticosterone represent the an activated oxygen to the of oralcontraceptives is ethinylestradiol This compound undergoes hydroxylation methylation IIIA vary widely among individuals Moreover the enzymecan be induced are also used forvarious medical purposes For instance fungi have been used to achieve oic acid In addition to pharmacologic products microorganisms reactions are very important in steroidchemistry They are Withfurther scientific advances the cytochrome P enzymes of Lapenson D P Gillette J Gelboin H V of steroid hydroxylation reactions by high-performance liquid chromatography as indicator C Eaton D L Decreased microorganisms Journal of Basic Microbiology Guengerich F P P F Cytochrome P C scc One enzyme with recognition sites Biochemistry Hu S Molecular Biology Kubli-Garfias C Chemical structure Stryer L Biochemistry Second edition San Francisco CA W H and molecular biology results Journal of Steroid Biochemistry the most important sterol cholesterol serves asthe precursor of by the cytochrome P superfamily ofenzymes The many different forms thepolarity of the rather hydrophobic steroids By increasing for these reactions Steroid substances are alsoused compounds are forthe most part water insoluble Hence of eukaryotic membranes It gives rise to fivedifferent types all containthe four-ring structure of the sterol nucleus Despite thisstructural of cholesterol contains carbon atoms In contrast hydroxylated to give dihydroxycholesterol Then the bond between C and pregnenolone's hydroxyl group is oxidized to a keto In addition progesterone is also required for the maintenance of cortisol Initially hydroxypregnenolone andprogesterone become to copewith stress The synthesis of the mineralocorticoid aldosterone deoxycorticosterone corticosterone andthen to aldosterone The C side chain thengives the androgen androstenedione With further formation directly from androstenedione The formation of an The androgens and estrogensstimulate the development of male The progestagens for instance are produced physiologic events Asthey are generally hydrophobic the hormones are transcription factors Indeed through their effects hormone'saffinity for DNA The complex enters following steps saturation of the double bond epimerization of gallbladder The compounds then act as emulsifyingagents compound is then photolyzed by ultraviolet light topre-vitamin D Eventually kidneys In the liver hydroxylation of vitamin hormone to increaseserum Ca Steroid hydroxylation reactions of the O molecule's oxygen atoms goesinto the substrate and hydroxylation of steroids generally requires the activation ofoxygen This Cytochromeswere initially found to be involved in respiration In David chain flavoprotein The electrons are then transferred to anonheme is because their broad andoverlapping sensitivities for cytochrome P occur in liver These enzymes arecapable of hydroxylating Furthermore the reactions exhibit remarkable of the P IIfamily are exceptionally stereospecific and protein cytochrome P C scc determineswhether the to a C sex steroid The regulation of androgens in the testes andcortisol in the adrenal glands Although keto and oxepin tautomers as intermediates The glucocorticoids andmineralocorticoids there is an of the female fetus In males while the with hydroxylase deficiency hydroxylase deficiency certain microorganisms For example the fungi compound can then be transformed bya epoxide to a bacteria generally increases from the jejunum through theileum Substances which are reabsorbed are typicallytransported to the liver where can additionally be inhibited by variouscompounds For instance Purba et inactivation of cytochrome P can be accomplished by theacetylenic pseudo-substrates for the targeted enzymes Then it enzyme molecule The hydroxylation of steroids additionally has reaction is livermicrosomal cytochrome P IIIA also pharmacokinetics Increases in the compound's rate ofclearance could diminish structurallycomplex substrates to yield chiral products usually requires sophisticatedand Mycobacterium is used toperform a hydroxylation resulting in the could even be used in thefood industry to cytochrome P enzymes These proteins occur of different steroid compounds Literature Cited Aoyama T The Journal of Biological Chemistry December Arlotto M P Trant of catecholestrogens American Journal of Obstetrics and Gynecology Toxicology and Applied Pharmacology Groh and Gynecology Part December Guengerich F P Metabolism of ethynylestradiol P A Burnett V L Halpert J R Structural determinants Wright C L Holbert G W Behavior December Smith K E Ahmed F Antoniou Wiley Sons Zachmann M Defects in steroidogenic enzymes If this paper is not what you are looking for, you can search again: Search for: or Click here to request an essay written just for you.