He studied this process by isolating a molecule in the adrenal glands, which are small glands located on top of each kidney that produce a variety of hormones. This molecule is able to lose and regain hydrogen atoms and contains six carbon atoms. It also contains properties of both sugar and an acid. He started to investigate the browning processes that interrupt growth and normal functioning. He found that plants begin to brown because of cellular damage.
This damage affects the mechanism that supplies hydrogen, which stops oxidation—a process in which one atom strips electrons from another, claiming them as its own. He found that browning could be caused by peroxidase, a plant enzyme that is active during oxidation. In his experiments he isolated the hexuronic acid substance that he thought was active within citrus juice. He started to work with a chemist named J. Guinea pigs are similar to humans, because they have to consume vitamin C to remain healthy.
This is because it cannot be made within their bodies. In this experiment, the animals were divided into two groups. One group of guinea pigs received boiled food, where the boiling process destroyed vitamin C. The other group was fed food that was enriched with hexuronic acid. The second group thrived and remained healthy, whilst the first group developed scurvy-like symptoms and later died.
He then had to find natural sources of vitamin C to complete his study. Orange juice and lemon juice contain high levels of ascorbic acid.
They also contain many sugars which makes it difficult to obtain a pure sample. Paprika is native to Szeged, Hungary. Suddenly it occurred to me that this is the one plant I had never tested. I took it to the laboratory… [and by] about midnight I knew that it was a treasure chest full of vitamin C. This was enough to give to the vitamin C-deficient guinea pigs and he determined that this acid was equivalent to vitamin C [ 5 ].
He studied cellular respiration processes within muscle cells and conducted experiments on the pectoral muscles of pigeons. He looked at the processes in this biochemical cycle that produce energy in the form of adenosine triphosphate ATP from proteins, carbohydrates, and fats. ATP is known to be the source of energy within cells. He noticed that ATP had a very important role. He also identified the role of fumaric acid in this process.
It is also called the tricarboxylic acid cycle due to the three-carboxyl groups found on its first two intermediates. This cycle contains eight steps that take place within the matrix of the mitochondria of the cell and is central to cellular respiration. The four-carbon molecule, oxaloacetate, which begins the cycle is regenerated after the eight steps Figure 2. He did pioneering work on the electron microscopy of muscle during this time, and discovered that muscle tissue stored in a 50 percent glycerin solution retained its contractility, so that researchers need not keep supplies of fresh muscle on hand.
Such preparations became widely used in muscle research. His elaborate theory about the mechanisms of cancerous cell growth argued that structural proteins in cells exchanged and conducted electrons in a very controlled way, making the cell's chemical work possible.
Devoted to doing basic research, he eventually refused to write funding applications that required him to say what the investigation would produce. His laboratory at Woods Hole flirted with financial disaster many times, and was rescued several times by funding from unlikely sources, such as the Armour meat company.
He was offered several academic appointments over the years, but declined them, fearing that teaching and faculty responsibilities would leave no time for research. He published many articles and several books addressing these topics, including The Crazy Ape They drew inspiration from his personal charm, his infectious enthusiasm for science, and his intuitive, playful approach to scientific questions.
He received the Nobel Prize in and a Lasker Award in The U. National Academy of Sciences elected him a member in Contact About. Home Biographical Overview. Hopkins, and spent one year at the Mayo Foundation, Rochester, Minnesota, before returning to Cambridge.
He described the interdependence of oxygen and hydrogen activation and made his first observations on co-dehydrases and the polyphenol oxidase systems of plants. He also demonstrated the existence of a reducing substance in plant and animal tissues.
At Cambridge and during his early spell in the United States, he isolated from adrenals this reducing substance, which is now known as ascorbic acid. Returning to Cambridge in , he later described the pharmacological activity of the nucleotides with Drury.
On his return to Hungary, he noted the anti-scorbutic activity of ascorbic acid and discovered that paprika Capsicum annuum was a rich source of vitamin C. His persistent studies of biological oxidation led to the recognition of the catalytic function of the C 4 -dicarboxylic acids, the discovery of «cytoflav» flavin and a recognition of the biological activity and probable vitamin nature of flavanone vitamin P.
In he commenced work on muscle research and quickly discovered the proteins actin and myosin and their complex.
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