I'll follow up with links to all the articles showing that glyphosate is safe for humans. This is important because there's a lot of misinformation out there and the news media are not doing a very good job of countering the hype against glyphosate by presenting the consensus views of the scientific community. It's time for scientists to push back and make sure the the media are doing the job they're supposed to do; informing the public.
Glyphosate is a relatively simple chemical called N-(phosphonomethyl) glycine. It is a potent inhibitor of one of the key enzymes in the pathway for synthesis of the aromatic amino acids, tryptophan, phenylalanine, and tyrosine [How Cells Make Tryptophan, Phenyalanine, and Tyrosine].
Specifically, the herbicide blocks the activity of EPSP synthase, the enzyme that catalyzes one of the steps leading to chorismate. Chorismate is the precursor of all three aromatic amino acids so by blocking this enzyme, the synthesis of three plant amino acids is prevented.
Plants need to synthesize all 20 amino acids so this blockage causes plants to die.
The glyphosate mechanism is well known from studies of the homologous bacterial versions of EPSP synthase. An example of glyphosate bound to the active site of the E. coli enzyme is shown on the right. When glyphosate is bound, the enzyme can't catalyze any reaction.
Animals have lost the ability to synthesize chorismate and the aromatic amino acids so they require tryptophan, phenyalanine, and tyrosine in their diet. What this means is that the potent herbicide, glyphosate, has no effect on animals since they have already dispensed with the EPSP synthase enzyme. That's one of the reasons why Roundup® is so safe for humans.
Those of you who have used Roundup® on your driveways and walkways know that it kills all plants indiscriminately. You'd better not get it on your wife's favorite roses (... not that I'm admitting anything, mind you).
You can't spray it on crops, such as soybeans, corn, cotton, granola, and wheat to get rid of weeds because it kills the crops as well as the weeds. Wouldn't it be nice to have Roundup® resistant crops so you could spray them to control weeds?
Monsanto makes Roundup® and and they thought so too. That's why their scientists searched for, and found, bacteria that were resistant to Roundup®. Then they transferred the gene for the resistant EPSP enzyme to various crop plants in order to make them resistant to Roundup®. [Roundup Ready® Transgenic Plants]
These Roundup Ready® crops are now found everywhere in Canada and the United States. Farmers routinely spray these crops with Roundup® in order to kill all the weeds in a field while saving the crop.
Since these farmers are handling tons of Roundup® every year, they would make a good group to examine for any adverse health effects, don't you think?
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