B-Hydroxybutyrate

Ostle, A., Holt, J.G., 1982. Nile blue A as a fluorescent stain for poly-b-hydroxybutyrate. 

Bissery, M. C., Valeriote, F., and Thies, C., Fate and effect of CCNU-loaded microspheres made of poly(D,L) lactide (PLA) or poly B-hydroxybutyrate (PHB) in mice, Proc. Int. Symp. Control. Rel. Bioact. Mater.. 12. 181, 1985. 

Figure 3. The effect of DL-B-hydroxybutyric acid ( HBA) and L-g-phenyllactic acid (BPLA) on C. album hypocotyl length (HL).

Poly-B-Hydroxybutyrate. It has been shown (11,12,13) that poly-B-hydroxybutyrate (PHB) is a head-to-tail polyester based on the monomer J) (-)-B-hydroxybutyric acid which leads to an optically active polymer having the formula ... 

Harrison MP, Jones DV, Pickford RJ, Wilson ID. B-Hydroxybutyrate a urinary marker of imipenem induced nephrotoxicity in the cynomolgus monkey detected by high field spectroscopy. Biochem Pharmacol 1991 41 (12) 2045-2049. 

In muscle, most of the fatty acids undergoing beta oxidation are completely oxidized to C02 and water. In liver, however, there is another major fate for fatty acids this is the formation of ketone bodies, namely acetoacetate and b-hydroxybutyrate. The fatty acids must be transported into the mitochondrion for normal beta oxidation. This may be a limiting factor for beta oxidation in many tissues and ketone-body formation in the liver. The extramitochondrial fatty-acyl portion of fatty-acyl CoA can be transferred across the outer mitochondrial membrane to carnitine by carnitine palmitoyltransferase I (CPTI). This enzyme is located on the inner side of the outer mitochondrial membrane. The acylcarnitine is now located in mitochondrial intermembrane space. The fatty-acid portion of acylcarnitine is then transported across the inner mitochondrial membrane to coenzyme A to form fatty-acyl CoA in the mitochondrial matrix. This translocation is catalyzed by carnitine palmitoyltransferase II (CPTII Fig. 14.1), located on the inner side of the inner membrane. This later translocation is also facilitated by camitine-acylcamitine translocase, located in the inner mitochondrial membrane. The CPTI is inhibited by malonyl CoA, an intermediate of fatty-acid synthesis (see Chapter 15). This inhibition occurs in all tissues that oxidize fatty acids. The level of malonyl CoA varies among tissues and with various nutritional and hormonal conditions. The sensitivity of CPTI to malonyl CoA also varies among tissues and with nutritional and hormonal conditions, even within a given tissue. Thus, fatty-acid oxidation may be controlled by the activity and relative inhibition of CPTI. 

Acetoacetate and b-hydroxybutyrate are both ketone bodies, as is acetone, a decarboxylation product of acetoacetate. The last acetyl CoA added is shown in purple. Note that since the methyl groups on acetone are indistinguishable, both... 

Ketone bodies (acetone, acctoacetale and B-hydroxybutyrate) may accumulate in the plasma of a diabetic patient. Their presence is by no means diagnostic of ketoacidosis, a serious condition. Ketones may be present in a normal subject as a result of simple prolonged fasting. Dry reagent strips which detect acetoacetate but not B-hydroxybutyrate might therefore provide an underestimate of kctonacmia / ketonuria. 

Kurcok, R Kowalczuk, M. Adamus, G. Jedlinrski, Z. and Lenz, R. W. Degradability of poly(b-hydroxybutyrate)s. Correlation with chemical microstucture. JMS-Pure Appl. Chem. 1995, 32,875-880. 

Doudoroff, M. and Stanier, R.Y. (1959) Role of poly-b-hydroxybutyric acid in the assimilation of organic... 

Ceding, V. and Schlegel, H.G. (1973) b-Ketothiolase from Hydrogenomonas eutropha H16 and its significance in the regulation of poly-b-hydroxybutyrate metabohsm. Biochemistry Journal, 134, 239-248. 

Schubert, R, Steinbiichel, A. and Schlegel, H.G. (1988) Cloning of the Alcaligenes eutrophus poly-b-hydroxybutyrate synthetic pathway and synthesis of PHB in Escherichia coli. Journal of Bacteriology, 170, 5837-5847. 

Rusendi, D. and Sheppard, J.D. (1995) Hydrolysis of potato processing waste for the production of poly-B-hydroxybutyrate. Bioresource Technology, 54, 191-196. 

Y-Amino-B-hydroxybutyric acid has been synthesised from ( )-malic acid, whilst a novel class of compounds were prepared by allowing protected amino-acids to react with partially protected... 

In general, however, the types of bacteria which produce such reserve polymers can be divided into two groups (1) those that produce PHAs in which X is 0 or 1 (that is, R is CH for poly-B-hydroxybutyrate, PHB, and/or C H for poly-R-hydroxyvalerate, PHV), and (2) those where x is... 

Senior, P. J. and Dawes, E. A. (1973). The regulation of poly-b-hydroxybutyrate metabolism in Azotobacter beijerinckii. Biochemical Journal 134, 225-238. 

Poly(b-hydroxybutyric acid), PHBA 3-hydroxy butyrate-valerate copolymer Polylactic acid, PLA, polyglycolides, polybutyric acid or copolymers of butyric and valeric acid... 

Kopinke, F.D., Mackenzie, K., Mechanistic aspects of the thermal degradation of polydactic acid) and poly(b-hydroxybutyric acid). / Anal Appl Pyrolysis 1997 40 43-53. 

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