Euler-Chelpin, OY luhr KEHL puhn, Hans Karl August Simon von (1873-1964), a German-born Swedish biochemist, carried out research into enzymes (substances that speed up chemical reactions in living organisms without themselves being changed) and the alcoholic fermentation of sugar. Euler-Chelpin's first work in biochemistry, in 1904, centered on the action of enzymes. During the early 1900's, he researched the chemistry of plants and fungi. Euler-Chelpin started research into vitamins in 1924 and helped to explain the structure of several vitamins. During the late 1920's, Euler-Chelpin returned to the chemistry of enzymes, including those called saccharase, urease, catalase, and zymase. He demonstrated that zymase was activated by vitamins A and B. In 1929, he was awarded the Nobel Prize for chemistry, sharing it with the British biochemist Arthur Harden (see Harden, Sir Arthur).