The Nobel Prize in Physiology or Medicine 1953
"for his discovery of the citric acid cycle”
1937
"for his discovery of co-enzyme A and its
importance for intermediary metabolism"
Sir Hans Adolf Krebs
Fritz Albert Lipmann
Sheffield University
United Kingdom
Harvard Medical School
Boston, MA, USA
At the University of Freiburg (1932), Krebs discovered (with the German biochemist Kurt Henseleit) a
series of chemical reactions (now known as the urea cycle) by which ammonia is converted to urea in
mammalian tissue;
GLICOLISI citoplasma
CH3-CO~CoA (acetil ~ COA)
mitocondrio
Ciclo di Krebs o Ciclo degli acidi tricarbiossilici o Ciclo del citrato
Via metabolica finale comune
- glucosio
- acidi grassi
- amminoacidi
ANAEROBIOSI
GLUCOSIO
2 LATTATO
2 ATP
AEROBIOSI
GLUCOSIO

2 PIRUVATO

2 NADH
2 ATP
5 ATP
2 NADH
5 ATP
2 ACETIL-CoA
3 NADH + H+
2 x 1 FADH2
1 GTP
7,5 ATP
2 x 1,5 ATP
1
ATP
10
ATP
20 ATP
TOT 32 ATP
CO2
BIOSINTESI
GLUCOSIO
piruvato principale via di entrata
aspartato
-BIOSINTESI LIPIDI
-acidi grassi
- colesterolo
BIOSINTESI UREA
fenilalanina
tirosina
BIOSINTESI E
CATABOLISMO AMMINOACIDI
metab. extra epatico corpi chetonici
BIOSINTESI EME - porfirina
Val
Ile
Met
glutammato
Ac grassi a catena dispari
Controllo: rapporto mitocondriale NAD+/NADH e stato energetico della cellula
3 deidrogenasi inibite da alti livelli NADH e bassi livelli di NAD+
acetil-CoA
isocitrato
(deidrogenasi)
ossalacetato
Inibita NADH
Attivata ADP
Inibita NADH
-chetoglutarato
(deidrogenasi)
malato
(deidrogenasi)
Inibita NADH
Inibita succinil-CoA
succinil-CoA