Quantitative Amino Acid-Protein Dynamics Nobel Lecture 2016

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Joseph Arabasz MD

Oct 1, 2020, 1:44:39 PM10/1/20
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Subject: Quantitative Amino Acid-Protein Dynamics, Nobel Lecture 2016

     Dietary Daily Protein Food recommendation is ~1gram/kg of body weight, eg ~70grams, however Protein Synthesis/day is 240grams mostly from Reutilization (170grams)

     These concepts make a big difference, since the implication is that if the MDR for Protein is really 240 grams/70kg = 3.5 g/kg/day vs 1g/kg/day, that might imply the 170 g/day of recycled Protein could be only a "turnover," catabolic event, which might be minimized if Amino Acid supply is adequate

    "Constitutive autophagy" is different from events to obtain Essential Amino Acids
Should differentiate the difference between destruction of used enzymes and those events which result from searching for deficient Amino Acids among Protein structures

Presumed Subject body weight is 70kg

Best wishes always

Thank you for your assistance with this matter


Joseph W Arabasz MD
S/P USAF, Top Secret 1964-69
University of Colorado at Boulder 1972, CU School of Medicine '75, '77, '83
Past Division Chairman, Anesthesiology, Cook County Hospital, Chicago, Illinois
Past Chairman, Respiratory Therapy, Cook County Hospital, Chicago
Diplomate ABA
Sigma Xi, The Professional Science Research Society
PO Box 6939
Denver, CO 80206


Autophagy- Nobel Lecture 2016

Dr Yoshinori
"Protein dynamics in the human body
The bulk of amino acids required for synthesis are met not through dietary intake, but the turnover of existing proteins in the cell

Blockage of the Reutilization Pathway for Amino Acids-Proteins, eg Essential B12 Vitamine methionine synthase enzyme with nitrous oxide, disrupts equilibrium and is perceived by the body as starvation


"Alternate forms of autophagy
-mentioned earlier that nutrient starvation is the most potent signal for the
induction of autophagy, representing a fundamental evolutionary adaptation to
the persistent challenge of nutrient limitation, starvation. In our work, we have
predominantly assessed autophagy in cells that have been subjected to starvation. 
But evolution is highly resourceful, and as with many highly-conserved core
cellular processes, autophagy has found a range of diverse applications in the
cell. In contrast to the canonical autophagy pathway, where induction is tightly
regulated and induced in response to starvation, constitutive forms of autophagy,
which occur continuously at a basal level in the cell, have also been uncovered.
Constitutive autophagy, the progress of which is independent of starvation,
is important for cytoplasmic homeostasis. 


Food Protein

Protein Synthesis



Excretion as Urea, Carbon Dioxide

Body Mass of 60kg Human is described as having Total Protein content of 9kg

Excretion as Urea, Carbon Dioxide


"Life is in an equilibrium state between synthesis and degradation of proteins. 

replacement of most proteins occurs every 3 months- “difference between organisms and machine” 

Recycling is essential for life important ability for survival against starvation"

critical selection factor in evolution 

Rudolf Schoenheimer (1898-1941)

J. Biol. Chem., 1939 “Protein Turnover” using isotope as a tracer


Use of Schoenheimer's scientific findings
Schoenheimer’s scientific work and his development of isotope tagging techniques enabled biochemists to discover the various metabolic pathways of the body

Schoenheimer was among the first scientists to identify that the bodies of humans and animals had processes of renewal and regeneration

The methods and techniques used by Schoenheimer also provided a means to measure quantities of substances within the body prior to the advent of the technologies and software for dynamic measurements

Schoenheimer’s 1933 metabolic balance study in animals presented early evidence of “end-product feedback inhibition of cholesterol synthesis”


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