scholarly journals The Biosynthesis of Monoterpenoids in Higher Plants. The Biosynthetic Pathway Leading to the Monoterpenoids from Amino Acids with a Carbon-skeleton Similar to Mevalonic Acid

1981 ◽  
Vol 54 (9) ◽  
pp. 2763-2769 ◽  
Author(s):  
Keiji Tange
1968 ◽  
Vol 46 (8) ◽  
pp. 931-935 ◽  
Author(s):  
L. R. Wetter ◽  
M. D. Chisholm

L-Methionine-35S and DL-cysteine-35S were good sources of sulfur for the biosynthesis of sinigrin in Armoracia lapathifolia Gilib. and were incorporated with approximately the same efficiency. Homomethionine-35S was a slightly poorer source of sulfur than methionine, while taurine-35S was a very poor source. When homomethionine, methionine, and cysteine were employed as sources of sulfur, the distribution of radioactivity between the two sulfur atoms in sinigrin was approximately 80% in the isothiocyanate moiety and 10–15% in the sulfate moiety. When taurine was employed, the distribution was reversed. 1-Thio-β-D-glucose (1-thioglucose) also was a poor source of sulfur for sinigrin. The carbon skeleton of 1-thioglucose was only slightly incorporated into this thioglucoside. The experiments indicated that 1-thioglucose was not a direct precursor of the 1-thioglucosyl residue of sinigrin.The administration of doubly labeled methionine-2-14C-35S clearly demonstrated that this amino acid was not incorporated intact into sinigrin. The carbon-2 and sulfur atoms were metabolized by two different routes.Preliminary studies related to sulfur incorporation into the thioglucosides of Nasturtium officinale R.Br., Tropaeolum majus L., and Reseda luteola L. indicated that there were some differences depending on the source of sulfur; DL-cysteine was a better source of sulfur than either methionine or 1-thioglucose. Tropaeolum majus L. appeared to utilize the sulfur of cysteine for the production of thioglucoside as efficiently as Armoracia lapathifolia Gilib.; however, the other two species utilized the sulfur from the amino acids very poorly.


1994 ◽  
Vol 195 (11) ◽  
pp. 3699-3707 ◽  
Author(s):  
Yoshio Inoue ◽  
Masayuku Fujita ◽  
Osamu Ohta ◽  
Kazuhiro Nakamura ◽  
Hiroko Kuroki ◽  
...  

Metabolites ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 334
Author(s):  
Yukinori Yabuta ◽  
Ryuta Nagata ◽  
Yuka Aoki ◽  
Ayumi Kariya ◽  
Kousuke Wada ◽  
...  

Ascorbate (AsA) is required as a cofactor and is widely distributed in plants and animals. Recently, it has been suggested that the nematode Caenorhabditis elegans also synthesizes AsA. However, its biosynthetic pathway is still unknown. To further understand AsA biosynthesis in C. elegans, we analyzed the incorporation of the 13C atom into AsA using gas chromatography-mass spectrometry (GC-MS) in worms fed with D-Glc (1-13C)-labeled Escherichia coli. GC-MS analysis revealed that AsA biosynthesis in C. elegans, similarly to that in mammalian systems, involves carbon skeleton rearrangement. The addition of L-gulono-1,4-lactone, an AsA precursor in the mammalian pathway, significantly increased AsA level in C. elegans, whereas the addition of L-galactono-1,4-lactone, an AsA precursor in the plant and Euglena pathway, did not affect AsA level. The suppression of E03H4.3 (an ortholog of gluconolactonase) or the deficiency of F54D5.12 (an ortholog of L-gulono-1,4-lactone oxidase) significantly decreased AsA level in C. elegans. Although N2- and AsA-deficient F54D5.12 knockout mutant worm (tm6671) morphologies and the ratio of collagen to non-collagen protein did not show any significant differences, the mutant worms exhibited increased malondialdehyde levels and reduced lifespan compared with the N2 worms. In conclusion, our findings indicate that the AsA biosynthetic pathway is similar in C. elegans and mammals.


1957 ◽  
Vol 35 (6) ◽  
pp. 365-371 ◽  
Author(s):  
E. Bilinski ◽  
W. B. McConnell

Glutamic acid, aspartic acid, and threonine isolated from the gluten of wheat plants to which acetate-1-C14 or -2-C14 was administered during growth have been degraded to determine the complete intramolecular distribution of C14. Sixty-three per cent of the activity in glutamic acid arising from acetate-1-C14 was in carbon-5 and 20% in carbon-1; glutamic acid from acetate-2-C14 contained 43% of the activity in carbon-4 and about 18% in each of carbons 2 and 3. Acetate-1-C14 resulted in labelling largely in the terminal carbons of aspartic acid, and acetate-2-C14 preferentially labelled the internal carbons. The results show that the Krebs' citric acid cycle provides a major pathway for the biosynthesis of the dicarboxylic amino acids of wheat gluten.Striking parallelism in the intramolecular distribution of carbon-14 in aspartic acid and threonine demonstrates that these amino acids are closely linked biosynthetically and is in accord with the idea that aspartic acid provides the carbon skeleton for threonine.


2004 ◽  
Vol 279 (44) ◽  
pp. 45728-45736 ◽  
Author(s):  
Toshihisa Kotake ◽  
Daisuke Yamaguchi ◽  
Hiroshi Ohzono ◽  
Sachiko Hojo ◽  
Satoshi Kaneko ◽  
...  

UDP-sugars, activated forms of monosaccharides, are synthesized throughde novoand salvage pathways and serve as substrates for the synthesis of polysaccharides, glycolipids, and glycoproteins in higher plants. A UDP-sugar pyrophosphorylase, designated PsUSP, was purified about 1,200-fold from pea (Pisum sativumL.) sprouts by conventional chromatography. The apparent molecular mass of the purified PsUSP was 67,000 Da. The enzyme catalyzed the formation of UDP-Glc, UDP-Gal, UDP-glucuronic acid, UDP-l-arabinose, and UDP-xylose from respective monosaccharide 1-phosphates in the presence of UTP as a co-substrate, indicating that the enzyme has broad substrate specificity toward monosaccharide 1-phosphates. Maximum activity of the enzyme occurred at pH 6.5–7.5, and at 45 °C in the presence of 2 mmMg2+. The apparentKmvalues for Glc 1-phosphate andl-arabinose 1-phosphate were 0.34 and 0.96 mm, respectively.PsUSPcDNA was cloned by reverse transcriptase-PCR.PsUSPappears to encode a protein with a molecular mass of 66,040 Da (600 amino acids) and possesses a uridine-binding site, which has also been found in a human UDP-N-acetylhexosamine pyrophosphorylase. Phylogenetic analysis revealed that PsUSP can be categorized in a group together with homologues fromArabidopsisand rice, which is distinct from the UDP-Glc and UDP-N-acetylhexosamine pyrophosphorylase groups. Recombinant PsUSP expressed inEscherichia colicatalyzed the formation of UDP-sugars from monosaccharide 1-phosphates and UTP with efficiency similar to that of the native enzyme. These results indicate that the enzyme is a novel type of UDP-sugar pyrophosphorylase, which catalyzes the formation of various UDP-sugars at the end of salvage pathways in higher plants.


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