BIOCHEMICAL PATHWAYS: Moris Friedkin and Albert Lehninger

By: Isabella Boushey, Camille Santos, & Ingrid Harb

Albert Lehninger• American biochemist born on February

17th, 1917 in Bridgeport, Connecticut. • Attended Wesleyan University as an

English major • Went to the University of Wisconsin where

he studied biochemistry and received his Ph.D in 1942

• Received several faculty positions at the University of Chicago and University of Wisconsin

• Went to the John Hopkins University School of Medicine

• Author of several classical texts such as Biochemistry, The Mitochondrion, and Bioenergetics.

Morris E. Friedkin• Born on December 30th, 1918 in Kansas City,

Missouri.• Attended Kansas City Junior College from

where he received an A.A. in chemistry • Continued his studies at Iowa State College

from where he received a B.S. in chemistry and an M.S. in analytical chemistry

• Enrolled in the doctorate program at the University of Chicago where he became one of the graduate students of Albert Lehninger

• Received his Ph.D in 1948• Received different faculty jobs at different

places • Devoted the rest of his life to teaching and

research• Research focused on folic acid metabolism,

the biochemical basis of the cell cycle and cell growth, the use of radioactively labeled molecules in biochemical research, molecular pharmacology, etc..

Timeline• 0. Eduard Buchner and Hans Buchner – discovers cell- free

fermentation• 1. Arthur Harden and William Young - in 1929, discovered

ATP• 2. Gustav Embden - first to discover and link together all

the steps involved in the conversion of glycogen to lactic acid

• 3. Otto Meyerhof & Jakub Parnas – known for The most common type of glycolysis is the Embden-Meyerhof-Parnas (EMP pathway)

• 4. Otto Heinrich Warburg – 1931, his research into cellular respiration showed that cancer thrives in anaerobic (without oxygen) or acidic conditions.

• 5. Albert Szent-Györgyi - was the first to isolate vitamin C, and his research on biological oxidation provided the basis for Krebs' citric acid cycle

• 6. Hans Adolf Kreb - 1937 Identification of citric acid cycle or "Krebs Cycle"

Experiments and Findings

•First started working with and studying fatty acids and how they work in the body

•Expanded interest to studying whole cell extracts

•Aim was to isolate a specific set of enzymes that catalyzed fat metabolism

•Separated the mitochondria through using dense sugar solution without damaging other organelles

Experiments and Findings• Set up a chilled centrifuge in a refrigerator • Found that the isolated mitochondria could

break down fatty acid chains, while the remaining parts of the cell could not

• The mitochondria also contained the enzymes for the citric acid cycle, as well as for the production of ATP

• It could not begin the breakdown of glucose• Lehninger identified the location of nearly all

the major energy reactions in the cell

Centrifuge

Experiments and Findings

•Lehninger's findings became very important in cell biology

• It was the first time that a specific function of a cell’s organelle had been proven

•This discovery showed that all functions of the cell were separated into different organelles that could be studied individually

Experiments and Findings• Had been concluded that for each oxygen the cell consumes

three ATP molecules are produced• Lehninger showed with the help of his student Morris Friedkin,

“the suspected role of electron transport through the cytochrome system.”

Experiments and Findings• Deduced that ATP was

produced from high energy electrons that are produced from NADH which is produced during the Kreb’s Cycle

• Able to show how NADH could be produced by using β-hydroxybutyrate

• He measured the oxygen consumption during this process using a classic apparatus designed by Warburg

Experiments and Findings•Made important conclusions on how ion

concentrations affected reaction rates•Shown through the synthesis of ATP through

the ETC when there is a high concentration of protons on the intermembrane space, which leads to protons diffusing from a high concentrated area to a lower concentrated area. This happens when the protons pass through the ATP synthase and trigger the reaction of the production of ATP.

References:• "Albert L. Lehninger." Medical Archives of The Johns Hopkins

Medical Institutions. N.p., n.d. Web. 17 Oct. 2012. <http://www.medicalarchives.jhmi.edu/sgml/lehninger.html>. 

• "forthcoming in New Dictionary of Scientific Biography." forthcoming in New Dictionary of Scientific Biography. N.p., n.d. Web. 17 Oct. 2012. <http://www.tc.umn.edu/~allch001/papers/lehninger.pdf>.

• "Friedkin, Morris. []." SNAC. N.p., n.d. Web. 17 Oct. 2012. <http://socialarchive.iath.virginia.edu/xtf/view?docId=friedkin-morris-cr.xml>. 

• "Mitochondria: A Historical Review." Mitochondria: A Historical Review. N.p., n.d. Web. 17 Oct. 2012. <http://jcb.rupress.org/content/91/3/227s.full.pdf>. 

• "The ATP Requirement for Fatty Acid Oxidation: the Early Work of Albert L. Lehninger." THE JOURNAL OF BIOLOGICAL CHEMISTRY. N.p., n.d. Web. 17 Oct. 2012. <http://www.jbc.org/content/280/14/e11.full.pdf>.