0-Hydroxybutyric acid

Higher than normal quantities of ketone bodies present in the blood or urine constitute ketonemia (hyperke-tonemia) or ketonuria, respectively. The overall condition is called ketosis. Acetoacetic and 3-hydroxybutyric acids are both moderately strong acids and are buffered when present in blood or other tissues. However, their continual excretion in quantity progressively depletes the alkah reserve, causing ketoacidosis. This may be fatal in uncontrolled diabetes mellitus. 

The following chemicals were obtained commercially (Sigma Chemical Co.) and bioassayed with C. album and Amaranthus retroflexus L. (seeds collected in North Carolina in 1980) following identification DL-3-hydroxybutyric acid (DL-3-hydroxy-butyric acid as a Na salt) and L-3-phenyllactic acid (L-2-hydroxy-3-phenyl-propanoic acid). 

Davis, S.C., Grate, I.H., Gray, D.R. et al. (2004) Enzymatic processes for the production of 4-substituted 3-hydroxybutyric acid derivatives. W02004015132. 

C4 = 3-hydroxybutyric acid, C5 = 3-hydroxyvaleric acid, C6 = 3-hydroxyhexanoic acid, C7 = 3-hydroxyheptanoic acid, C8 = 3-hydroxyoctanoic acid, C9 = 3-hydroxynonanoic acid CIO = 3-hydroxydecanoic acid. 

Polyesters, such as microbially produced poly[(P)-3-hydroxybutyric acid] [poly(3HB)], other poly[(P)-hydroxyalkanoic acids] [poly(HA)] and related biosynthetic or chemosynthetic polyesters are a class of polymers that have potential applications as thermoplastic elastomers. In contrast to poly(ethylene) and similar polymers with saturated, non-functionalized carbon backbones, poly(HA) can be biodegraded to water, methane, and/or carbon dioxide. This review provides an overview of the microbiology, biochemistry and molecular biology of poly(HA) biodegradation. In particular, the properties of extracellular and intracellular poly(HA) hydrolyzing enzymes [poly(HA) depolymerases] are described. 

DIRECT DEGRADATION OF THE BIOPOLYMER POLY[(R)-3-HYDROXYBUTYRIC ACID] TO (R)-3-HYDROXYBUTANOIC ACID AND ITS... 

A, (R)-(-)-Methyl 3-hydroxybutanoate. A 2-L, round-bottomed flask is charged with 50 g (0.58 mol) of poly-[(R)-3-hydroxybutyric acid] (PHB) (Note 1) and 500 mL of absolute 1,2-dichloroethane. The flask is equipped with a reflux condenser, and the mixture is heated at reflux lor 1 hr. A solution of 10 mL of coned sulfuric acid in 200 mL of absolute methanol is added and the reaction mixture is heated at reflux for 3 days. During this time the mixture becomes homogeneous. 

The submitters used PHB=Poly-(R)-3-hydroxybutyric acid obtained from Marlborough Biopolymers Ltd., Rudby Hall, Hutton Rudby, Yarm, Cleveland, England, PHB homopolymer, BX G04, technical grade powder, MBL 100/703. The checkers used PHB from Fluka Chemie AG, CH-8470 Buchs, Switzerland. The submitters report that the procedure works well on batch sizes of 200-250 g. 

Allen and DuBois136 have calculated that the R. Q. of 0.707, obtainable when fat is completely oxidized, would be lowered to 0.669 if the /3-hydroxybutyric acid were not metabolized. If more than one molecule of the ketone bodies is produced from one molecule of the fatty acid, as has been suggested,83 the R. Q. would be further lowered. This may be further complicated by a resulting upset in acid-base balance. 

Dioxanone derivatives.1 The optically active 1,3-dioxanone (acetal lactone) 1 is obtained by reaction of (R)-3-hydroxybutyric acid with pivalaldehyde in the presence of an add catalyst. These derivatives can be used to effect enantio-selective reactions at the 2-, 3-, and 4-positions of (R)-3-hydroxybutyric acid. Thus,... 

The C4 aldol intermediate of the Weizmann process is also key in the aerobic fermentation of sugars to poly(3-hydroxybutyric acid) or PHB (-0[-CH(CH3)-CH2-COO - [70]. This natural and biodegradable polymer is produced inside microorganisms, e.g., Ralstonia eutropha. A complex processing is required to extract and purify the polymer granules from the microorganism. 

Vicibactin (18) (previously called hydroxamate K (61a)) from Rhizobium legu-minosarum is a macrocyclic trilactone consisting of A -acetyl-Ai -hydroxy-D-Om and (/ )-3-hydroxybutyric acid (91). 

During anaerobic glycolysis in the muscles and erythrocytes, glucose is converted into lactate, releasing protons in the process (see p. 338). The synthesis of the ketone bodies acetoacetic acid and 3-hydroxybutyric acid in the liver (see p. 312) also releases protons. Normally, the amounts formed are small and of little influence on the proton balance. If acids are formed in large amounts, however (e. g., during starvation or in diabetes mellitus see p. 160), they strain the buffer systems and can lead to a reduction in pH (metabolic acidoses lactacidosis or ketoacidosis). 

In 23-cpoxybutyric acid sodium borohydride opened the epoxide ring without affecting the carboxyl. Varying ratios of 2- and 3-hydroxybutyric acid were obtained depending on the reaction conditions. Sodium borohydride in alkaline solution gave 18% of a- and 82% of -hydroxybutyric acid while in the presence of lithium bromide the two isomers were obtained in 60 40 percentage ratio [1000]. 

It may be stated at this point that the presence of a /3-hydroxy-butyrate fat in certain organisms is a matter of general biochemical importance. Usually /3-hydroxybutyric acid and the acetone bodies are derived from n-butyric acid directly. The unambiguous formation of jS-hydroxybutyric acid anhydrides from carbohydrates opens up new vistas its formation from acetaldehyde, and from pyruvic acid, through aldol intermediates can be understood without difficulty. Kirrmann s reaction, to which little attention has been paid, is at the same time an example of an oxygen shift, leading from hydroxyaldehydes to fatty acids. 

Figure 3 shows parts of the in vivo metabolic route towards PHAs. The biosynthesis of poly(3-hydroxybutyric acid) (P3HB) requires the condensation of two... 

Two of the three attractant pheromones identified to date are very close structurally to those used in primary metabolism. The biosynthesis of the estolide 5 probably starts from 3-hydroxybutyric acid (4), an intermediate in fatty acid biosynthesis (Fig. 4.3). Condensation of two units furnishes the pheromone 5. The formation of cupilure (3 Fig. 4.2) can be easily explained by two methylations from ubiquitous citric acid. Both compounds are unlike any known insect pheromones, whereas the third known attractant pheromone (ketone 1 Fig. 4.1), bears some resemblance to some insect pheromones. A proper comparison of the differences and similarities between insect and arachnid pheromones will require the identification of representative compounds from most of the families of both groups of organisms. 

Amino-3-hydroxybutyric acid [924-49-2] M 119.1, m ZlS fdec). Crystd from H2O or aqueous EtOH. 

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-(3-hydroxybutyric acid and the light-colored granules of unknown nature. Courtesy of F. D. Williams, Gail E. VanderMolen, and C. F. Amstein.

The important bacterial storage material poly-hydroxybutyric acid is related metabolically and structurally to the lipids. This highly reduced polymer is made up of D-(3-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 0.60 nm.a Within bacteria it often occurs in thin lamellae 5.0 nm thick. Since a chain of 1500 residues stretches to 440 nm, there must be 88 folds in a single chain. Present in both cytoplasmic granules and in membranes,b polyhydroxybutyrate can account for as much as 50% of the total carbon of some bacterial In E. coli and many other bacteria polyhydroxybutyrate is present in a lower molecular mass form bound to calcium polyphosphates, proteins, or other macromolecules.d e It has also been extracted from bovine serum albumin and may be ubiquitous in both eukaryotes and prokaryotes.d/e The polymer may function in formation of Ca2+ channels in membranes.b/d... 

Oxidation of thioethers derived from the natural chirality pool , the readily available lactic acid and 3-hydroxybutyric acid, has been used in molar-scale preparation of enantiomerically pure sulfoxides methyl ( )-2-(phenylsulfinyl)acrylate and (K)-isopropenyl p-tolyl sulfoxide [107]. 

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