3-D-hydroxybutyrate

Further resonances attributable to the CFI3 groups of ketone bodies, predominantly 3-D-hydroxybutyrate, were also found in all synovial fluid samples studied. These data indicate an elevated utilization of frits for energy, despite the overall hypoxic environment of the synovial tissue (Merry et al., 1991 Henderson etal., 1993). 

Plasma Glucose Pyruvate Acetate Lactate 3-D-hydroxybutyrate ... 

Tissues other than liver utilize ketone bodies by first reoxidizing /3-d-hydroxybutyrate to acetoacetate (see Figure 19.10) and then converting acetoacetate to acetoacetyl-CoA. The latter occurs via a mitochondrial thiophorase reaction [Equation (19.8)] or a cytosolic acetoacetate CoA synthetase reaction [Equation (19.9)] ... 

Enzymes catalyzing reactions (19.8) and (19.9) are present in very minor amounts in the liver, and hence liver is a ketone body exporter rather than user. Acetoacetyl-CoA is converted to two acetyl-CoA molecules by the action of a thiolase, and the acetyl-CoA is used in the Krebs cycle. 1 mol /3-D-hydroxybutyrate... 

D-(-) HYDROXYBUTYRATE DEHYDROGENASE FROM RAT LIVER MITOCHONDRIA PURIFICATION AND INTERACTION WITH PHOSPHOLIPIDS... 

In addition to standard abbreviations, the following are employed HBD, 3-D-(-) hydroxybutyrate dehydrogenase apoHBD,... 

Fig. 3.22. GC separation of keto and hydroxy acids from the urine of a patient with maple syrup urine disease. Top chromatogram, the patient before dietary treatment middle chromatogram, the same patient after two days on a diet bottom chromatogram, a mixture of reference compounds. Peaks 1, lactic acid 2, 2-hydroxyisobutyric acid 3, 2-hydroxybutyric acid 4, pyruvic acid 5, 3-hydroxyisobutyric acid 6, 3-hydroxybutyric acid 7, 2-hydroxyisovaleric acid 8, 2-ketobutyric acid 9, malonic acid (internal standard) 10, 2-methyl-3-hydroxybutyric acid 11, 2-hydroxy-n-valeric acid 12. methylmalonic acid 13, 3-hydroxyisovaleric acid 14a and b, 2-ketoisovaleric acid IS, acetoacetic add 16, 2-hydroxyisocaproic acid 17, 2-hydroxy-3-methylvaleric acid 18a, L-2-keto-3-methylvaleric add 18b, D-2-keto-3-methyl-valeric acid 19, 2-ketoisocaproic acid. Reproduced from [386],...

A random copolyester of 3HB and 4-hydroxybutyric acid, P(3HB-co-4HB), was produced by A. eutrophus (Kunioka et al., 1988, 1989 Nakamura et al., 1992), A. latus (Hiramitsu et al., 1993) or Comamonas acidovorans (Saito and Doi, 1994), when dr-hydroxybutyric acid, l,4r-butanediol or y-butyrolactone was used as the carbon source. The P(3HB-co-4HB) copolymers with a wide range of compositions from 0 to 100 mol% 4HB was produced by A. eutrophus bora the mixed carbon substrates of 3-hydroxybutyric and 4-hydroxybutyric acids in the presence of some additives (Nakamura et al., 1992). When drhydroxybutyric acid, citrate, and ammonium sulfate were fed to A. eutrophus, P(3HB-co-4HB) copolymers with compositions of 70-100 mol% 4HB were produced. In contrast, C. acidovorans produced a P(4HB) homopolymer in the presence of 1,4-butanediol or d-hydroxybutyric acid without additives (Saito and Doi, 1994). 

Figure 7.3 Different enzymes involved in the degradation of aliphatic polyesters. d-PHB Poly(D-hydroxybutyrate) PBS polybutylene succinate and PBSA polybutylene succinate-adipate. Reproduced with permission from Y. Tokiwa and B.P. Calabia,of Polymers and the Environment, 2007, 15,...

Starting liom the respective blends, the PVA/poly(lactic acid) (PLA), PVA/poly (capro lacton) (PCL), and PVA/poly(hydroxybutyrate) (PHB), and applying the standard treatment including extraction of PVA with water, the 3-D structures have been observed (Fig. 6.8). 

Fig. 10.1 Metabolites in the urine of an untreated patient with branched-chain keto aciduria (maple syrup urine disease). Extracted using ethyl acetate and separated as their trimethylsilyl-oxime derivatives on a 25 m SE-30 capillary column, using temperature programming from 80°C to 110°C at 0.5°C min and an injection split ratio 1 12 at a temperature of 250°C. The peaks marked R are due to solvent and reagents. Peak identifications are 1, lactic 2, 2-hydroxyisobutyric 3, 2-hydroxybutyric 4, pyruvic 5, 3-hydroxybutyric 6, 2-hydroxyisovaleric 7, 2-oxobutyric 8, 2-methyl-3-hydroxy-isovaleric 10, a and b, 2-oxoisovaleric 11, acetoacetic 12, 2-hydroxyisocaproic 13, 2-hydroxy-3-methyl- -valeric 14, 2-oxo-3-methyl-/i-valeric (14a L- 14b D-) 15, 2-oxoisocaproic acids. The internal standard was malonic acid. (Redrawn with modifications from Jellum etal., 1976)...

L-Homoserine (2-amino-4-hydroxybutyric acid) [672-15-1] M 119.1, m 203", [cc]d +18.3" (in 2M HCI), pKEst(i) -2.1, pl st(2) 3. Likely impurities are A -chloroacetyl-L-homoserine, N-chloroacetyl-D-homoserine, L-homoserine, homoserine lactone, homoserine anhydride (formed in strong solns of homoserine if slightly acidic). Cyclises to the lactone in strongly acidic soln. Crystd from water by adding 9 volumes of EtOH. 

Most of the acetyl-CoA formed by 3-oxidation in liver is converted to acetoacetate by the 3-hydroxy-3-methylglutaryl-CoA pathway (Guzman and Gelen, 1993). Acetoacetate is reversibly converted to D-3-hydroxybutyrate by D-3-hy-droxybutyrate dehydrogenase in the mitochondrial matrix in all tissues. 

Yamane, T., 1996. Yield of poly-D-(-)-3-hydroxybutyrate from various carbon sources a... 

Under metabolic conditions associated with a high rate of fatty acid oxidation, the liver produces considerable quantities of acetoacetate and d(—)-3-liydroxyl)utyrate (P-hydroxybutyrate). Acetoacetate continually undergoes spontaneous decarboxylation to yield acetone. These three substances are collectively known as the ketone bodies (also called acetone bodies or [incorrectly ] ketones ) (Figure 22-5). Acetoacetate and 3-hydroxybu-... 

Figure 22-5. Interrelationships of the ketone bodies. D(-)-3-hydroxybutyrate dehydrogenase is a mitochondrial enzyme.

In most cases, ketonemia is due to increased production of ketone bodies by the liver rather than to a deficiency in their utilization by extrahepatic tissues. While acetoacetate and d(—)-3-hydroxybutyrate are readily oxidized by extrahepatic tissues, acetone is difficult to oxidize in vivo and to a large extent is volatilized in the lungs. 

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. 

Fig. 1. The metabolic cycle for the synthesis and degradation of poly(3HB). (1) 3-ketothiolase (2) NADPH-dependent acetoacetyl-CoA reductase (3) poly(3HB) synthase (4) NADH-dependent acetoacetyl-CoA reductase (5), (6) enolases (7) depolymerase (8) d-(-)-3-hydroxybutyrate dehydrogenase (9) acetoacetyl-CoA synthetase (10) succinyl-CoA transferase (11) citrate synthase (12) see Sect. 3...

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