Khan Academy lessons:
Let's explore what enzymes are, and how they can affect a reaction. The most important affect you need to know is its ability to "catalyze" the reaction. By Ross Firestone.Created by Ross Firestone.
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Scurvy did not emerge as a problem for maritime explorers until vessels started penetrating the Indian and the Pacific Oceans. Vasco da Gama lost two thirds of his crew to the disease while making his way to India in 1499. In 1520 Magellan lost more than 80 per cent while crossing the Pacific...more
Vitamin C (ascorbic acid) plays important roles as an anti-oxidant and in collagen synthesis. These important roles, and the relatively large amounts of vitamin C required daily, likely explain why most vertebrate species are able to synthesize this compound. Surprisingly, many species, such as teleost fishes, anthropoid primates, guinea pigs, as well as some bat and Passeriformes bird species, have lost the capacity to synthesize it...more.
Pepsin is the principal acid protease of the stomach. It is generally recognized as the first enzyme to be discovered (in the eighteenth century) and was named by T. Schwann in 1825. Pig pepsin was the second enzyme, after urease, to be crystallized... more...