Herbicides, Roundup glyphosate

All carbons are derived from either erythrose 4-phosphate (light purple) or phosphoenolpyruvate (pink). Note that the NAD+ required as a cofactor in step (3) is released unchanged it may be transiently reduced to NADH during the reaction, with formation of an oxidized reaction intermediate. Step (6) is competitively inhibited by glyphosate (COO—CH2—NH—CH2—PO ), the active ingredient in the widely used herbicide Roundup. The herbicide is relatively nontoxic to mammals, which lack this biosynthetic pathway. The chemical names quinate, shikimate, and chorismate are derived from the names of plants in which these intermediates have been found to accumulate. 

In recent years, agribusiness firms have developed pf empirically several compounds that inhibit essential steps in the biosynthesis of amino acids found in plants but missing in animals. One of these compounds, glyphosate, is a highly specific inhibitor of 5-enol pyruvyl-shikimate-3-phosphate synthase (an enzyme needed for aromatic amino acid biosynthesis). Glyphosate is the active ingredient in the widely used herbicide Roundup. 

Figure 5.8 Roundup is a contact herbicide containing glyphosate. container contains the liquid concentrate which is diluted prior to use.

The advantage for the farmer is that he needs only one product, instead of several different selective (and more expensive) herbicides. Roundup ready soybeans were launched in 1996 and today 50 percent of the soybean crop in the United States is derived from roundup ready seeds. Other glyphosate-resistant transgenic crops introduced by Monsanto are maize and oil seed rape. Competing companies also developed herbicide-resistant plants or plants genetically modified to be protected against certain pests, but none has achieved a commercial breakthrough, mainly because of political reasons. 

N-(Phosphonomethyl) glycine. This material, closely related chemically and probably biologically to Polaris, has been given the generic name of glyphosate. As the isopropylamine salt, it is the very potent herbicide Roundup which is especially active on grasses. It has been tested as the isopropylamine salt, as the acid, and in several other forms as a ripener on sugarcane and was found to be extremely active—in fact, much more active than Polaris itself. 

Williams GM, Kroes R, and Munro IC (2000) Safety evaluation and risk assessment of the herbicide Roundup and its active ingredient, glyphosate, for humans. Regulatory Toxicology and Pharmacology 31 117-165. 

A/-(phosphonomethyl)-glyciae isopropylamiae salt [38641-94-0 ] [22224-92-6 ] [26264-05-1 ] From Diisopropylamine [2303-16-4] Roundup / glyphosate herbicide... 

Glyphosate - a bulk active herbicide. One of the world s leading herbicides is glyphosate (Roundup) (21) produced by Monsanto. They key intermediate is disodium iminodiacetate (DSIDA) (20). 

Transgenic soybean plants expressing the CTP-CP4 EPSPS display commercial levels of Roundup tolerance. These results vaUdate the importance of substrate kinetics of EPSPS in order to maintain adequate rates of aromatic biosynthesis. Furthermore, the fact that glyphosate tolerance can be obtained by expression of a glyphosate-tolerant EPSPS illustrates that the herbicidal mode of action of glyphosate is related solely to inhibition of the EPSPS reaction. 

Progress in Heterocyclic Chemistiy (PHC) Volume 9 reviews critically the heterocyclic literature published mainly in 1996. The first two chapters are review articles. Chapter 1 by C.J. Moody and K.J. Doyle deals with "The Synthesis of Oxazoles from Diazocarbonyl Compounds," and Chapter 2 by J.A. Sikorski provides a detailed account of the heterocyclic chemistry suiTounding the remarkable herbicide glyphosate ("Roundup" ). This latter chapter illustrates the role that heterocyclic chemistry plays in other areas of modem chemistry, since glyphosate is a far cry from being heterocyclic ... 

Precursors of phenylpropanoids are synthesized from two basic pathways the shikimic acid pathway and the malonic pathway (see Fig. 3.1). The shikimic acid pathway produces most plant phenolics, whereas the malonic pathway, which is an important source of phenolics in fungi and bacteria, is less significant in higher plants. The shikimate pathway converts simple carbohydrate precursors into the amino acids phenylalanine and tyrosine. The synthesis of an intermediate in this pathway, shikimic acid, is blocked by the broad-spectrum herbicide glyphosate (i.e., Roundup). Because animals do not possess this synthetic pathway, they have no way to synthesize the three aromatic amino acids (i.e., phenylalanine, tyrosine, and tryptophan), which are therefore essential nutrients in animal diets. 

Other carboxylic acids that have become popular herbicides, though they are not phenoxyacetic acid derivatives, are dicamba and glyphosate or Roundup . Notice that dicamba does have a methoxy group and two chlorines, so it is similar to 2,4-D. Glyphosate is used on cotton and... 

For example, the EU recently cleared the herbicide glyphosate (Roundup), which is practically nontoxic to humans, for consumer use. Nevertheless, KEMI has notified importers and distributors that sales of glyphosate to the public will be severely restricted in the future. Faithful to its socialist traditions, the almighty Swedish State attaches no value to the billions of Swedish crowns invested by private homeowners in lawns, flowerbeds, rose gardens, and so on. An appeal to KEMI s decision will most likely be directed to the European Court of Justice. 

She is referring to the GE crops that are engineered with a bacterial protein that makes them tolerant to the herbicide glyphosate. This is the main component of Monsanto s Roundup, (box 5.2). Conventional farmers like these GE crops because they can spray the herbicide on the weeds. The weeds die, and even if the herbicide drifts onto the GE crop, the crop will survive. Because no hoeing or cultivating is needed, herbicide-tolerant GE crops are now widely grown. 

Roundup The brand name for the glyphosate herbicide produced by Monsanto used to control weeds. 

For example, glyphosate (Roundup )—the largest selling herbicide, particularly for genetically engineered plants and food crops—has been implicated in human health cases. 

Monsanto Company, Toxicology of Glyphosate and Roundup Herbicide, Department of Medicine and Environmental Health, St. Louis, MO, 1985. 

The herbicide glyphosate (Roundup ) kills plants by inhibiting an enzyme needed for synthesis of phenylalanine. Deprived of phenylalanine, the plant cannot make the proteins it needs, and it gradually weakens and dies. Although a small amount of glyphosate is deadly to a plant, its human toxicity is quite low. Suggest why this powerful herbicide has little effect on humans. 

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