The Biological Catalysis Enzyme:

Biological catalysis  are called enzyme. An enzyme can be defined as an organic  substance that tremendously accelerates a chemical  reaction without changing  its  direction  and is neither  used up nor permanently  altered in the rection  so that it can  be sued  again  and again ,Enzyme  are dtudied under the branch enzymology  .First indication of the occurrence of enzymes in living systems was given  by Kirchhoff 1815 who prepared a wheat extract that could catalyze transformation of starch into sugar. There after Louis pastier 1860 discovered that  the fermentation of foodstuffs can be brought about by yeast cells .Kuhne 1878 discovered  that in fact  a ferment present in yeast cell.  Brings about  this fermentation .He called  this ferment  an enzyme presumably   about 3000 kinds  of enzymes  are required to catalyze  metavolic  reaction  in an ordinary cell. All ezymes  are synthesized   within   the cell  itself under genic  control, Scientists  have  so far  identified about 2000 enzymes . They  have however  ascertained that these enzyme can catalyze reactions even outside the cells . A few hundred  enzymes  have been extracted in pure form  and pure crystals  of many of these have been prepared. Buchner1897  was first to prepare a pure extract  of zymase enzyme from  yeast. The  Noble  laureate sumner 1926 first prepared  pure crystals of urease enzyme  from  jack beans Northrop 1930  gastric and  pancreatic juices .He also  postulated that chemically all enzymes are proteins.