Delta-9 desaturase

Eigenheer, A. L., Young, S. D., Blomquist, G. J., Borgeson, C. E., Tillman, J. A. and Tittiger, C. (2002) Isolation and molecular characterization of Musca Domestica delta-9 desaturase sequences. Insect Molec. Biol. 11, 533-542. 

Thomas, C. (2000). A delta 9 desaturase gene with a different substrate specificity is responsible for the cuticular diene hydrocarbon polymorphism in Drosophila melanogaster. Proc. Natl. Acad. Sci. USA, 97, 9449-9454. de Renobales, M., and Blomquist, G. J. (1984). Biosynthesis of medium chain fatty acids in Drosophila melanogaster. Arch. Biochem. Biophys., 228,407 114. 

Biochemical and molecular characterizaton of house cricket (Acheta domesticus, Orthoptera Gryllidae) Delta 9 desaturase. Insect Biochem. Mol. Biol., 32, 1731-1740. 

Tiku, RE., Gracey, A.Y., Macartney, A.I., Beynon, R. J., and Cossins, A.R. (1996). Cold-induced expression of delta 9-desaturase in carp by transcriptional and posttranslational mechanisms. Science, 271, 815-818. 

The endoplasmic reticulum is a site for the introduction of double bonds ( desaturation ) into fatty acids. The pathway used is almost universal, having been identified in bacteria, yeasts, algae, higher plants, protozoa and animals. Examples are the conversion of stearic acid (18 0) to oleic acid (18 ln-9) and of palmitic acid (16 0) to palmitoleic acid (16 ln-7) by the insertion of a cis double bond between carbons 9 and 10. Because the double bond is inserted between carbons 9 and 10 counting from the carboxyl end of the acyl chain, the desaturase enzyme is known as delta-9 desaturase (A -desaturase), although sometimes this enzyme is referred to as stearoyl CoA (coenzyme A) desaturase. 

Turpeinen et al. (2002) have shown that consuming 1.5, 3.0 or 4.5 g per day tra 5-vaccenic acid produced a dose-dependent increase in total serum cis-9,trans- CLA concentration, presumably by the action of hepatic delta-9-desaturase. While this indicates that humans possess some capacity for cis-9,trans- CLA biosynthesis, the increments in the concentration of this isomer were similar to those produced by ingesting equivalent doses of preformed cis-9,trans- CLA. This suggests that there is no major advantage of consuming tran -vaccenic acid as a source of cis-9, trans-ll CLA. 

Fox BG, ShankUn J, Somerville C, Miinck E. 1993. Stearoyl-acyl carrier protein Delta-9 desaturase from Ricinus communis is a diiron-oxo protein. Proc Natl Acad Sci USA 90 2486-2490. 

Shu LJ, Broadwater JA, Achim C, Fox BG, Munck E, Que Jr L. 1998. EXAFS and Mossbauer characterization of the diiran(in) site in stearoyl-acyl carrier protein Delta(9) desaturase. JBiol Inorg Chem 3 392—400. 

Yang YS, Baldwin J, Ley BA, Bollinger Jr JM, Solomon El. 2000. Spectroscopic and electronic structure description of the reduced binuclear non-heme iron active site in ribonucleotide reductase from E. colt comparison to reduced Delta(9) desaturase and electronic structure conttibutions to differences in O2 reactivity. J Am Chem Soc 122 8495-8510. 

Broadwater JA, Ai JY, Loehr TM, Sanders-Loehr J, Fox BG. 1998. Peroxodiferric intermediate of stearoyl-acyl carrier protein Delta(9) desaturase oxidase reactivity during single timiover and implications for the mechanism of desaturation. Biochemistry 31 4664- 461. ... 

Yang YS, Broadwater JA, Pulver SC, Fox BG, Solomon EL 1999. Circular dichroism and magnetic circular dichroism studies of the reduced binuclear non-heme iron site of stearoyl-ACP Delta(9)-desaturase substrate binding and comparison to ribonucleotide reductase. J Am Chem Soc 121 2770-2783. 

Davydov R, Behrouzian B, Smoukov S, Smbbe J, Hoffinan BM, Shanklin J. 2005. Effect of substrate on the diiron(III) site in stearoyl acyl carrier protein Delta(9)-desaturase as disclosed by cryoreduction electron paramagnetic resonance/electron nuclear double resonance spectroscopy. Biochemistry 44 1309-1315. 

Behrouzian B, Buist PH, Shanklin J. 2001. Application of KIE and thia approaches in the mechanistic study of a plant stearoyl-ACP Delta(9) desaturase. Chem Commun 401 02. 

Griinari JM, Cori BA, Lacy SH, Chouinard PY, Nurmela KVV, and Bauman DE. 2000. Conjugated linoleic acid is synthesized endogenously in lactating dairy cows by delta(9)-desaturase. J. Nutn, 130, 2285. 

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