Gustav Embden, Otto Meyerhof and Jakub Parnas

By : Brunette K and Melissa K

JAKUB PARNAS

Jakub Parnas

Was a prominent Jew-Polish–Soviet biochemist Contributed to the discovery of the Embden–Meyerhof–Parnas pathway His major work was the study of the mechanisms of carbohydrate metabolism

in muscle tissue He discovered the process of phosphorolysis Contributed to the analysis of Glycolysis He also studied the metabolism of animals tissues He used the rabbit in this case He injected L(+/)and D (-) lactic acids to rabbits and analyzed its content

in particular organs like muscles and urine Was able to prove that L and D forms of lactate are differently

metabolized He concluded that L (+) lactic acid is quickly removed from tissues,

whereas D(-) lactate is extremely slowly metabolized and its toxic

Cont..

Did an experiment on the connection between the breaking down of glycogen and lactic acid formation

Did the experiment on tissues homogenate and on perfused organs

Him and Wagner performed the experiment on resting and working isolated frog muscle in oxidative and anaerobic conditions

Their result concluded that the decrease of carbohydrate content in working muscles is accompanied by lactate formation whereas in anaerobic conditions much less lactate is present, less is formed, or is metabolized further

OTTO MEYERHOF

OTTO MEYERHOF

*German biochemist born in 1884 and died in 1951 * In 1919 He showed that during muscle contraction

where oxygen is not present ,glycogen is converted to lactic acid

*Furthermore, he showed in the presence of oxygen a small amount of lactic acid is broken down into Carbon dioxide and water

* In 1925 he extracted the group of enzyme that help in the conversion of glycogen to lactic acid from muscle

CONT..

* He studied metabolism of sea-urchin eggs * He found a coenzyme of alcoholic fermentation *studied the respiration of killed cells * He discovered a co-enzyme of respiration * Meyerhof showed that the unsaturated fatty acids in the cell are

oxidized with the help of the sulphydryl group * He extracted from the muscle of a frog the enzymes that convert

glycogen to lactic acid * observed that in the absence of oxygen in the muscle, lactic acid

appears slowly in the relaxed state and rapidly in the active state, and that this lactic acid disappears again in the presence of oxygen

*concluded that oxygen is only involved in the relaxed state of a muscle

GUSTAVE EMBDEN

GUSTAV EMBDEN

German biochemist *Carried studies on Carbohydrate metabolism and muscle

contraction * He was the first to find a connection between the steps of

conversion of glycogen to lactic acid *He conducted his studies mostly in living organisms

especially in organs such as the liver *He studied the metabolic processes in liver tissues * From his studies on liver tissues he concluded that the organ

plays a significance role in metabolism * His conclusion led him to further studies that led to the

researches of normal sugar metabolism and of diabetes

Cont..

* In 1924 he discovered that compared to the processes in the yeast cell glucose has to be broken down to an ester product in order to breakdown further

In 1927 he discovered what is now named as “Embdem ester” in the muscle cells

By the time of his death (1933) him and his assistant traced all the steps of conversion of glycogen to lactic acid

Cont..

Embden noticed that results would be unsatisfactory if experiment were conducted on both undissected and dissected animals

Consequently he used a perfusion technique to conduct experiments using the livers of warm blooded animals

The new perfusion method helped keep the dissected liver intact As a result he found out that oxidative deamination is a way to

break down the synthesis reaction of sugar to lactic acid His results also showed that metabolism in liver is highly

significant His studies on carbohydrate metabolism led him to an interest in

chemical processes in muscular activity His work led to the discovery of adenyl phosphoric acid in the

muscle that open a new large field in biochemistry

REFERENCES

› http://dictionary.reference.com/browse/embden-meyerhof+pathway

› http://www.jbc.org/content/280/4/e3› http://books.google.ca/books?id=XOyjZX0

Wxw4C&pg=PR57&dq=otto+meyerhof+experiments&hl=en&ei=9bekTrbEGcrd0QGTr8DeDA&sa=X&oi=book_result&ct=result&resnum=3&ved=0CDcQ6AEwAg#v=onepage&q=otto%20meyerhof%20experiments&f=false

› http://books.google.ca/books?id=XxUqWDwwIewC&pg=PA10&dq=gustav+embden+experiments&hl=en&ei=GW-kTojtJ8rx0gG4sKifBQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCwQ6AEwAA#v=onepage&q=gustav%20embden%20experiments&f=false