Zymase is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

complex that catalyzes the fermentation of

sugar Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or double ...

into

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...

and

carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...

. It occurs naturally in

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitut ...

s. Zymase activity varies among yeast strains. Zymase is also the brand name of the drug

pancrelipase Pancreatic enzymes, also known as pancreases or pancrelipase and pancreatin, are commercial mixtures of amylase, Pancreatic lipase family, lipase, and protease. They are used to treat malabsorption syndrome due to certain Exocrine pancreatic insu ...

Cell-free fermentation experiment

Zymase was first isolated from the yeast cell in 1897 by a German chemist named

Eduard Buchner Eduard Buchner (; 20 May 1860 – 13 August 1917) was a German chemist and zymologist, awarded the 1907 Nobel Prize in Chemistry for his work on fermentation. Biography Early years Buchner was born in Munich to a physician and Doctor Extraor ...

who fermented sugar in the laboratory without living cells, leading to 1907 Nobel Prize in Chemistry. The experiment for which Buchner won the Nobel Prize consisted of producing a cell-free extract of

cells and showing that this "press juice" could ferment sugar. This dealt yet another blow to

vitalism Vitalism is a belief that starts from the premise that "living organisms are fundamentally different from non-living entities because they contain some non-physical element or are governed by different principles than are inanimate things." Wher ...

by showing that the presence of living yeast cells was not needed for fermentation. The cell-free extract was produced by combining dry yeast cells,

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...

and

kieselguhr Diatomaceous earth (), diatomite (), or kieselgur/kieselguhr is a naturally occurring, soft, siliceous sedimentary rock that can be crumbled into a fine white to off-white powder. It has a particle size ranging from more than 3 μm to le ...

and then pulverizing the yeast cells with a mortar and pestle. This mixture would then become moist as the yeast cells' contents would come out of the cells. Once this step was done, the moist mixture would be put through a press and when this resulting "press juice" had

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...

fructose Fructose, or fruit sugar, is a Ketose, ketonic monosaccharide, simple sugar found in many plants, where it is often bonded to glucose to form the disaccharide sucrose. It is one of the three dietary monosaccharides, along with glucose and galacto ...

, or maltose added,

was seen to evolve, sometimes for days. Microscopic investigation revealed no living yeast cells in the extract. Buchner hypothesized that yeast cells secrete proteins into their environment in order to ferment sugars. It was later shown that fermentation occurs inside the yeast cells. British chemist Sir

Arthur Harden Sir Arthur Harden, FRS (12 October 1865 – 17 June 1940) was a British biochemist. He shared the Nobel Prize in Chemistry in 1929 with Hans Karl August Simon von Euler-Chelpin for their investigations into the fermentation of sugar and ferment ...

divided zymase into two varieties (dialyzable and nondialyzable) in 1905. Some science historians suggest that

, in his 1897 work, merely repeated experiments already made by

Antoine Béchamp Pierre Jacques Antoine Béchamp (16 October 1816 – 15 April 1908) was a French scientist now best known for breakthroughs in applied organic chemistry and for a bitter rivalry with Louis Pasteur. Béchamp developed the Béchamp reduction ...

in 1857. This is not the case : what Buchner obtained with yeast zymase, and without yeast cells, was alcoholic fermentation, while Béchamp had explicitly stated that, in absence of yeast cells, and by use of what he, also, called "zymase", he obtained only sugar inversion and no alcoholic fermentation. According to K.L. Manchester,Keith L. Manchester : "Antoine Béchamp: père de la biologie. Oui ou non?", ''Endeavour'', Vol. 25, n° 2, 1 juny 2001, pp. 68–73; Keith L. Manchester : "Louis Pasteur, fermentation, and a rival", ''South African Journal of Science'', vol. 103 (2007)
online
what Béchamp called "zymase" was

invertase Invertase is an enzyme that catalyzes the hydrolysis (breakdown) of sucrose (table sugar) into fructose and glucose. Alternative names for invertase include , saccharase, glucosucrase, beta-h-fructosidase, beta-fructosidase, invertin, sucrase, m ...

References

Enzymes