Glycerol biosynthesis

Pahlman, A.K., Granath, K., Ansell, R., Hohmann, S., and Adler, L., 2001, The yeast glycerol 3-phosphatases Gpplp and Gpp2p are required for glycerol biosynthesis and differentially involved in the cellular responses to osmotic, anaerobic, and oxidative stress. J. Biol. Chem. 276(5) 3555-3563. 

IdaY, Hirasawa T, Furusawa C, Shimizu H. Utilization of Saccharomyces cerevisiae recombinant strain incapable of both ethanol and glycerol biosynthesis for anaerobic bioproducfron. App/ Microbiol Biotechnol 2013 97 4811-9. 

G. Griffiths, Ph. D. Thesis "Aspects of Triacyl glycerol Biosynthesis... 

Blank ML, Smith ZL, Snyder F. Arachidonate-containing triacyl-glycerols biosynthesis and a lipolytic mechanism for the release and transfer of arachidonate to phospholipids in HL-60 cells. Biochim Biophys Acta 1993 1170 275-282. 

Figure 4.6 The bifunctional enzyme PRA-isomerase (PRAI) IGP-synthase (IGPS) catalyzes two sequential reactions in the biosynthesis of tryptophan. In the first reaction (top half), which is catalyzed by the C-terminal PRAI domain of the enzyme, the substrate N-(5 -phosphoribosyl) anthranilate (PRA) is converted to l-(o-carboxyphenylamino)-l-deoxyribulose 5-phosphate (CdRP) by a rearrangement reaction. The succeeding step (bottom half), a ring closure reaction from CdRP to indole-3-glycerol phosphate (IGP), is catalyzed by the N-terminal IGPS domain.

Phosphatidic acids not only are intennediates in the biosynthesis of triacylglycerols but also are biosynthetic precursors of other members of a group of compounds called phosphoglycerides or glycerol phosphatides. Phosphorus-containing derivatives of lipids are known as phospholipids, and phosphoglycerides are one type of phospholipid. 

Phosphatidic acid, the parent compound for the glycerol-based phospholipids (Figure 8.4), consists of 5w-glycerol-3-phosphate, with fatty acids esterified at the T and 2-positions. Phosphatidic acid is found in small amounts in most natural systems and is an important intermediate in the biosynthesis of the more common glycerophospholipids (Figure 8.6). In these compounds, a... 

Diacylglycerol is glycerol esterified to two fatty acids at the sn-1 and sn-2 positions. It is a membrane-embedded product of phospholipase C action and an activator of protein kinase C. It is also an intermediate in the biosynthesis of triacylglycerol, phosphatidyletha-nolamine and phosphatidylcholine. 

Figure 24-2. Biosynthesis of triaq/lglycerol and phospholipids. ( , Monoacylglycerol pathway (D, glycerol phosphate pathway.) Phosphatidylethanolamine may be formed from ethanolamine by a pathway similar to that shown for the formation of phosphatidylcholine from choline.

How the aliphatic monomers are incorporated into the suberin polymer is not known. Presumably, activated co-hydroxy acids and dicarboxylic acids are ester-ified to the hydroxyl groups as found in cutin biosynthesis. The long chain fatty alcohols might be incorporated into suberin via esterification with phenylpro-panoic acids such as ferulic acid, followed by peroxidase-catalyzed polymerization of the phenolic derivative. This suggestion is based on the finding that ferulic acid esters of very long chain fatty alcohols are frequently found in sub-erin-associated waxes. The recently cloned hydroxycinnamoyl-CoA tyramine N-(hydroxycinnamoyl) transferase [77] may produce a tyramide derivative of the phenolic compound that may then be incorporated into the polymer by a peroxidase. The glycerol triester composed of a fatty acid, caffeic acid and a>-hydroxy acid found in the suberin associated wax [40] may also be incorporated into the polymer by a peroxidase. 

As precursors for the biosynthesis of fats (lipogenesis), the adipocytes use triacylglycerols from lipoproteins (VLDLs and chylomicrons see p. 278), which are formed in the liver and intestines and delivered by the blood. Lipoprotein lipase [1], which is located on the inner surface of the blood capillaries, cleaves these triacylglycerols into glycerol and fatty acids, which are taken up by the adipocytes and converted back into fats. 

A second esterification of this type leads to a phosphatidate (enzyme l-acylglycerol-3-phosphate acyltransferase 2.3.1.51). Unsaturated acyl residues, particularly oleic acid, are usually incorporated at C-2 of the glycerol. Phosphatidates (anions of phosphatidic acids) are the key molecules in the biosynthesis of fats, phospholipids, and glycolipids. 

Transfer of an additional acyl residue to DAG forms triacylglycerols (enzyme diacyl-glycerol acyltransferase 2.3.1.20). This completes the biosynthesis of neutral fats. They are packaged into VLDLs by the liver and released into the blood. Finally, they are stored by adipocytes in the form of insoluble fat droplets. 

This enzyme [EC 2.4.2.18], also referred to as phospho-ribosyl-anthranilate pyrophosphorylase, catalyzes the reaction of anthranilate with phosphoribosylpyrophos-phate to produce A-5 -phosphoribosylanthranilate and pyrophosphate. In certain species, this enzyme is part of a multifunctional protein, together with one or more other components of the system for the biosynthesis of tryptophan (i.e., indole-3-glycerol-phosphate synthase, anthranilate synthase, tryptophan synthase, and phos-phoribosylanthranilate isomerase). 

C. Schaffrath, C.D. Murphy, J.T.G. Hamilton, D. O Hagan, Biosynthesis of fluoroace-tate and 4-fluorothreonine in Streptomyces cattleya. Incorporation of oxygen-18 from [2- H,2- 0]-glycerol and the role of serine metabolites in fluoroacetaldehyde biosynthesis, J. Chem. Soc. Perkin Trans. 1 (2001) 3100-3105. 

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