Lecture 7 Slides
rh
Great new Krebs cycle (Citric Acid cycle) movie…
http://www.youtube.com/watch?v=A1DjTM1qnPM
fig 16-13
Krebs cycle
features and
functions…
fig 16-13
it’s all about acetate…
O
CH3-C
O-
O
CH3-C
O
CH3-C
acetyl group
S-CoA
AcCoA
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acetate
acetyl coenzyme A
or
acetyl-CoA
all roads lead to acetyl-CoA…
fig16-1
electrons from acetyl groups
fig16-1
energy from electrons
fig16-1
This is HS-CoA, or CoA-SH, CoA, or coenzyme A
fig16-3
This is HS-CoA, or CoA-SH, CoA, or coenzyme A
CoA-SH, or HS-CoA, or CoA
fig16-3
where the acetyl groups come from
pyruvate dehydrogenase: PDH
fig16-2
Thiamine pyrophosphate (TPP): an activated carbon
fig 14-13
TPP as a carbanion
nucleophile in pyruvate
metabolism
fig 14-13
Lipoic acid cofactor of PDH E2
The “business
end” of PDH
fig16-4
The PDH complex
fig16-5
approx. 4.5 x 106 MW
The PDH complex
fig16-5
The PDH
catalytic
cycle
fig16-6 (old)
oxidation of pyruvate
Several reactions, one basic location
fig16-6
Please read and
LEARN
“The Name Game”
The:
Krebs cycle
citric acid
cycle
TCA cycle
fig16-7
Citrate synthase and its substrates…
fig 16-8
Getting fresh carbons into the act
why it’s called the citric acid cycle
pg 622
making citrate asymmetric
remember this for later…
pg 622
an iron-sulfer cluster in aconitase
fig16-10
electrons!
NADH is the main carrier of
Krebs cycle-derived electrons
pg 624 (less fancy picture)
more electrons!
note CoA-SH has
re-entered the picture
pg 625
direct production of a high energy phosphate
but not ATP…
instead it’s GTP
pg 626
direct production of a high energy phosphate
but not ATP…
instead it’s GTP
pg 626
electrons to FAD instead of NAD+
pg 628
The business end of FAD or FMN
isoalloxazine
ring
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electrons to FAD instead of NAD+
pg 628
a sensible inhibitor of succinate
dehydrogenase
pg 628
Hydration of fumarate
old pg 612
Hydration of fumarate
pg 628
high specificity exemplified by substrates and products
of fumarase
not a
substrate
substrate
product
pg 628
high specificity exemplified by substrates and products
of fumarase
substrate
product
not a
product
pg 628
the final electron removal
pg 628
Krebs cycle
features and
functions…
fig 16-13