Fatty acids, dihydroxy

Labeque, R. and Marnett, L.J. (1988). Reaction of hematin with allylic fatty acid hydroperoxides identification of products and implications for pathways of hydroperoxide-dependent epoxidation of 7,8-dihydroxy-7,8-dihydrobenzo [a]pyrene. Biochemistry 27, 7060-7070. 

Alkyl PAT, alkyl-dihydroxy phosphate synthase Bif, bifunctional enzyme DHAPAT, dihydroxyphosphate acyltransferase deficiency DHCA, dihydroxycholestanoic acid N, normal nd, not determined Ox, acyl-CoA oxidase Rac, 2-methylacyl-CoA racemase RCDP, rhizomelic chondrodysplasia punctata Ref, Refsum s disease THCA, trihydroxycholestanoic acid VLCFA, very-long-chain fatty acid. 

In a few cases, 3-hydroxy fatty acids that contain additional functional groups were characterized. Thus (i )-3-hydroxydodec-(5Z)-enoic add [A5-12 l(3-OH)] was identified in ester linkage in lipid A of the chloridazon-de-grading bacterium P. immobile (105). Unsaturated 3-hydroxy fatty adds are also present in R. trifolii (81) and R. meliloti (82). In an extract of L. pneumophila, 2,3-dihydroxy-12-methyltridecanoic acid [12-Me-13 0(2,3-diOH)] and 2,3-dihydroxytetradecanoic acid [ 14 0(2,3-diOH)] were identified in amide-linkage (138). It remains, however, to be established, whether these 2,3-dihydroxylated fatty acids are lipid A constituents. Small amounts of 2-methyl-3-hydroxy-fatty adds have been detected in B. pertussis (139). 

Sugar The hydrolysis of sucrose in the intestine produces both glucose and fructose, which are transported across the epithelial cells by specific carrier proteins. The fructose is taken up solely by the liver. Fructose is metabolised in the liver to the triose phosphates, dihydroxy-acetone and glycer-aldehyde phosphates. These can be converted either to glucose or to acetyl-CoA for lipid synthesis. In addition, they can be converted to glycerol 3-phosphate which is required for, and stimulates, esterification of fatty acids. The resulting triacylglycerol is incorporated into the VLDL which is then secreted. In this way, fructose increases the blood level of VLDL (Chapter 11). 

Garbe L-A, Tressl R (2004) Metabolism of deuterated t/jreo-dihydroxy fatty acids in Saccha-romyces cerevisiae Enantioselective formation and characterization of hydroxylactones and y-lactones. Helv Chim Acta 87 180... 

In plants a-dioxygenases (Chapter 18) convert free fatty acids into 2(R)-hydroperoxy derivatives (Eq. 7-3, step d).32a These may be decarboxylated to fatty aldehydes (step e, see also Eq. 15-36) but may also give rise to a variety of other products. Compounds arising from linoleic and linolenic acids are numerous and include epoxides, epoxy alcohols, dihydroxy acids, short-chain aldehydes, divinyl ethers, and jasmonic acid (Eq. 21-18).32a... 

Esterification with a fatty acid or with ferulic acid at C-3 of triterpene alcohols exerted almost no influence on the activity as has been observed with lupane- (264/265) and cycloartane- (66/67, 72/73) type compounds and a C-3 monohydroxy triterpenoid (264/266). However, esterification at C-3 with a fatty acid reduced the inhibitory activity of some dihydroxy triterpenoids (138/139,140 202/203, 204 230/231 232/233, 234). 

From the sea anemone M. senile was isolated j3-glucopyranosyl-( 1 - l)-ceramide, the structure of which was determined by mass spectrometry, H-n.m.r. spectroscopy, and chemical splitting. The major sphingosine in the cerebroside is a new base containing two double bonds and branching at one double bond, namely, 2-amino-D-eryf/jro-l,3-dihydroxy-9-methyl-( , E)-octadeca-4,8-diene. The major fatty acids are Ci6 0 and C20 o a-hydroxy acids.133... 

The major, fatty acid component in these glycolipids is the C22 , acid, and no hydroxy acids were found. The sphingosine bases are represented by dihydroxy bases, among which, the preponderant one is the C,8 sphin-... 

Considerable proportions of cerebroside have been detected in the starfish Asterias rubens.9Ail0 It is a glucosylceramide having a-hydroxy fatty acids (from C16 to C26) and dihydroxy bases whose major components are Cl8 and C22 bases, with one, or two, double bonds. 

Additionally, microbial systems convert unsaturated fatty acids to monohydroxy-, dihydroxy- and trihydroxy-fatty acids (Hou, 1995,2000). It is feasible to produce various value-added hydroxy fatty acids and derivatives for industrial applications by exploiting the unique reaction specificities of excep-... 

Another dihydroxy fatty acid, 10,12-dihydroxy-8( )-octadecenoic acid (DHOD), was produced as an intermediate in the conversion of ricinoleic acid to 7,10,12-trihydroxy-8( )-octadecenoic acid (TOD) by PR3 (Fig. 31.2) (Kim... 

Based on the postulated common metabolic pathway involved in DOD and TOD formation by PR3, it was assumed that palmitoleic acid containing a singular C9 cis double bond (a common structural property shared by oleic and ricinoleic acids), could be utilized by PR3 to produce hydroxy fatty acid. Bae et al. (2007) reported that palmitoleic acid could be utilized as a substrate for the production of hydroxy fatty acid by PR3. Structural analysis of the major product produced from palmitoleic acid by PR3 confirmed that strain PR3 could introduce two hydroxyl groups on carbon 7 and 9 with shifted migration of 9-cis double bond into 8-tram configuration, resulting in the formation of 7,10-dihydroxy-8( )-hexadecenoic acid (DHD) (Fig. 31.3).The time course study of DHD production showed that DHD formation was time-dependently increased, and peaked at 72 h after the addition of palmitoleic acid as substrate. However, production yield of DHD (23%) from palmitoleic acid was relatively low when compared to that of DOD (70%) from oleic acid (Hou and Bagby, 1991). 

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