P-hydroxybutyric acid

Ascorbic acid is involved in carnitine biosynthesis. Carnitine (y-amino-P-hydroxybutyric acid, trimethylbetaine) (30) is a component of heart muscle, skeletal tissue, Uver and other tissues. It is involved in the transport of fatty acids into mitochondria, where they are oxidized to provide energy for the ceU and animal. It is synthesized in animals from lysine and methionine by two hydroxylases, both containing ferrous iron and L-ascorbic acid. Ascorbic acid donates electrons to the enzymes involved in the metabohsm of L-tyrosine, cholesterol, and histamine (128). 

A mixture of 5 g of aluminum amalgam, 5 g of acetoacetic acid p-phenetidide and 50 ml of ethanol are gently heated for 30 minutes. After filtering off the reducing agent with suction, water is added to the filtrate, and the latter is then acidified with 2 N hydrochloric acid. p-Hydroxybutyric acid p-phenetidide melting at 160°C crystallizes in almost quantitative yield in the form of white crystals. 

SYNS BETADID BUCETIN BUTANAMIDE, N-(4-ETHOXYPHENYL)-3-HYDROXY- BUTYRANILIDE, 4 -ETHOXY-3-HYDROXY- 4 -ETHOXY-3-HYDROXY-BUTYRANILIDE P-HYDROXYBUTYRIC ACID-p-PHENETIDIDE P-OXYBUTTERSAEURE-p-PHENETIDID... 

HYDROXYBUTYRIC ACID Y-LACTONE see BOVOOO P-HYDROXYBUTYRIC ACID-p-PHENETIDIDE see HJS850... 

Figure 1-3 A cell of a Spirillum negatively stained with phosphotungstic acid. Note the tufts of flagella at the ends, the rough appearance of the outer surface, the dark granules of poly-p-hydroxybutyric acid and the light-colored granules of unknown nature. Courtesy of F. D. Williams, Call E. VanderMolen, and C. F. Amstein.

The PHA produced by the transformed cyanobacterial cells was identified by GC-MS analysis. The constituents of PHA of the cyanobacterial cells were 3-hydroxybutyric acid, lactic acid, and other unknown hydroxyalkanoic acids, and the major constituent was p-hydroxybutyric acid. The average molecular weight (M.W.) of PHA produced by the cyanobacterial cells was about 1,000,000, similar to the average M.W. of PHA from Alcaligenes eutrophus. 

Z,-(+)-hydroxybutyric acid Ascorbic acid Z)Z,-P-hydroxybutyric acid Imidazolelactic acid Imidazole-4-acetic acid L-glutamic acid... 

Recently, it was reported that acetals derived from homochiral P-hydroxybutyric acid react with R3Cu2Li in the absence of BF3-OEt2. These reactions proceed with highly diastereoselective anti displacement of the carboxylate, and treatment of the product with base liberates a secondary alcohol of high enantiomeric purity. 

The msgor acids produced by the body include phosphoric acid, sulfuric acid, lactic acid, and the ketone bodies, acetoacetic acid and p-hydroxybutyric acid. C02 is also produced, which combines with H20 to form carbonic acid in a reaction catalyzed by carbonic anhydrase... 

Hypoventilation causes retention of C02 by the lungs, which can lead to a respiratory acidosis. Hyperventilation can cause a respiratory alkalosis. Metabolic acidosis can result from accumulation of metabolic acids (lactic acid or the ketone bodies p-hydroxybutyric acid and acetoacetic acid), or ingestion of acids or compounds that are metabolized to acids (methanol, ethylene glycol). Metabolic alkalosis is due to increased HC03, which is accompanied by an increased pH. Acid-base disturbances lead to compensatory responses that attempt to restore normal pH. For example, a metabolic acidosis causes hyperventilation and the release of C02, which tends to lower the pH. During metabolic acidosis, the kidneys excrete NH4+, which contains H+ buffered by ammonia. 

Ammonia is released into the urine, where it buffers the hydrogen ions produced by phosphoric acid, sulfuric acid (produced from cysteine), and various metabolic acids (e.g., lactic acid and the ketone bodies, ace-toacetic acid and P-hydroxybutyric acid). 

During prolonged starvation or when carbohydrate metabolism is severely impaired, as in uncontrolled diabetes mel-iitus (see Chapter 25), the formation of acetyl-CoA exceeds the supply of oxaioacetate. The abundance of acetyl-CoA results from excessive mobilization of fatty acids from adipose tissue and excessive degradation of the fatty acids by p-oxidation in the liver. The resulting acetyl-CoA excess is diverted to an alternative pathway in the mitochondria and forms acetoacetic acid, P-hydroxybutyric acid, and acetone—three compounds known collectively as ketone bodies (Figure 26-9). The presence of ketone bodies is a frequent finding in severe, uncontrolled diabetes melUtus. 

Strong acids, such as sulfuric, hydrochloric, and phosphoric, are fully ionized at the pH of urine and are excreted only after the H" derived from these acids reacts with a buffer base. Excretion of the anions of these acids is accompanied by the simultaneous removal of an equal number of cations, such as Nak IC, or NHJ, to provide electrochemical balance. However, some acids, such as acetoacetic acid (piC = 3.58) and p-hydroxybutyric acid (piC= 4.7), are present in blood almost entirely in ionized form at the acid pH frequently prevailing in urine, some are nondissociated and thus may be excreted partially as the nondissociated acid (see Figure 46-11). For example, 50% of 3-hydroxybutyric acid at pH 4.7 is nonionized. 

Production of organic acids that exceeds the rate of elimination (e.g., the production of acetoacetic acid and p-hydroxybutyric acid in diabetic acidosis and of lactic acid in lactic acidosis). 

Paraldehyde toxicity may develop after chronic paraldehyde ingestion. The pathogenesis is poorly defined, but the acidosis may actually be a ketosis (nitroprusside negative) with P-hydroxybutyric acid as the main acidic product. Patients with paraldehyde toxicity have a pungent, apple-like odor to their breath. 

Another example where metabolic pathway engineering has made a dramatic impact is in the biodegradable polymer field. The polymer of this family most widely studied is poly-P-hydroxybutyrate (PHB) (46). Another member of the PHA family commercialized by Imperial Chemical Industries (ICI), which later became Zeneca under the trade name Biopol, is a copolymer consisting of p-hydroxybutyric acid and P-hydroxyvaleric acid. This biodegradable polymer was first used in plastic shampoo bottles by the Wella Corporation [198]. In the early part of 1996, the Biopol product line, was purchased from Zeneca by the Monsanto Company. 

The SPE method used by the Miami-Dade County Medical Examiner s Office, Toxicology Laboratory, in Miami, Florida (Andollo and Hearn, 1998) uses Chem-Elute - SPE columns, p-hydroxybutyric acid internal standard, pretreatment of urine with sulfuric acid and pretreatment of blood with sodium tungstate and sulfuric acid. The Dade County method gave an absolute recovery of 30% with a limit of detection of 2 pg mL and a limit of quantitation of 10 pgmL ... 

Abbreviations A, acetone ASES, aerosol solvent extraction system DM, dichloromethane DMF, A/,A/-dimethyl-formamide E, ethanol GAS, gas antisolvent process H, hexane HYAFF-11, hyaluronic acid benzylic ester I, isopropanol PAN, polyacrylonitrile PCA, precipitation with compressed antisolvent PCL, polycaprolactone PHB, poly(p-hydroxybutyric acid) PLA, polylactic acid PLGA, poly(lactic-co-glycolic acid) SAS, supercritical antisolvent process SEDS, solution enhanced dispersion by supercritical fluids TFE, 2,2,2-trifluoroethanol Triblock polymer, p poly(L-lactide-CO-D,L-lactide-co-glycolide)(62.5 1 2.5 25). 

Cranberry is available in a variety of forms such as fresh or frozen cranberries, cranberry juice cocktail, other cranberry drinks, cranberry sauce, and powder in hard or soft gelatin capsules (Hughes and Lawson, 1989 Siciliano, 1996). Cranberries are approx 88% water and contain flavonoids, anthrocyanins (odain), cetechin, triterpinoids, P-hydroxybutyric acid, citric acid, malic acid,... 

A systematic study of urinary or blood organic acids has not yet been made with this method, which can be improved through combination with chromatography (B12). Electrophoresis has, however, been used for some special cases, as for the separation of lactic and P-hydroxybutyric acids, which are difficult to separate by paper chromatography (07). 

Hydroxybutyric Acid. P-Hydroxybutyric acid is present in normal human plasma (at a concentration of 0.3-0.9mg%) (K14) and in normal urine (F2). 

Metabolic acid-base disorders are those which directly cause a change in the bicarbonate concentration. Examples incluile diabetes mcliitus. where altered intemiediary metabolism in the absence of insulin cau.ses a build up of hydrogen ion from the ioni/ation of aceloacetic and P-hydroxybutyric acids, or loss of bicarbonate from the extracellular Iluid. e.g. from a duodenal fistula. 

The important bacterial storage material poly-hydroxybutyric add is related metabolically and structurally to the lipids. This highly reduced polymer is made up of o-P-hydroxybutyric acid units in ester linkage, about 1500 residues being present per chain. The structure is that of a compact right-handed coil with a twofold screw axis and a pitch of... 

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