Cell Metabolism 2 Flashcards
intermediates in the tca cycle
can - citrate
i - isocitrate
keep - a-keto glutarate
selling - succinyl CoA
substances - succinate
for - fumerate
money - malate
officer - oxaloacetate
(ox + A-CoA => citrate)
net products of tca
2NADH + 1FADH2 + 1GTP + 2CO2
= 12ATP
krebs enzymes
soluble
in mitochondrial matrix
amino acid degradation (+ which 7 molecules formed)
amino group removed + carbon skeleton funnelled into glucose production/tca
pyruvate, A-CoA, acetoacetyl-CoA, akg, succinyl-CoA, fumerate, oxloacetate
ketogenic vs glucogenic amino acid
ketogenic = degraded into acetyl CoA
glucogenic = undergoes glycogenesis = glucose
transamination
group transfer
amine group from amino acid to keto acid = new pair
purpose of glycerol-phosphate shuttle
shuttle NADH from cytosol into matrix in skeletal muscle + brain
purpose of malate-aspartate shuttle
shuttle NADH from cytosol into matrix in kidney, liver, heart
which tca mutations can lead to cancer + how
mutations in genes coding iso-citrate dehydrogenase, succinate dehydrogenase and fumerase
causes warburg effect: preferential generation of lactate from glucose even in low O2 (increased glycolysis + decreased tca)
fa vs carb metabolism
fa = double caloric yield
brain cant use fa
acyl coA synthesis
FA + ATP + HS-CoA ===> Acyl CoA + AMP + PPi
(acyl-CoA synthase)
purpose of carnitine shuttle
transfer of acyl CoA from cytoplasm to mito matrix through translocase
primary carnitine deficiency
autosomal recessive
mutation in SLC22A5 which encodes carnitine transporter = carnitine not up taken by cell
encephalopathy, muscle weakness, cardiomyopathy and hypoglycaemia in childhood
beta oxidation
catabolic process by which fatty acid molecules are broken down in mitochondria (acyl CoA => acetyl CoA)
no: turns = (no: carbons/2) -1
b-ox of palmitic acid
16C palmitic acid + 7FAD + 7NAD + 7H2O + 7CoA
= 8CoA + 7FADH2 + 7NADH
= 129 ATP
when are ketone bodies formed
when no carb metabolism as acetyl CoA cant enter TCA without oxaloacetate
e.g during fasting
name 3 ketone bodies
acetoacetate
acetone
D-3 hydroxybutyrate
which enzymes are involved in ketone body production
3 ketothiolase
HMG CoA synthase
HMG CoA cleavage enzyme
D-3-hb dehydrogenase
fatty acid biosynthesis
sequential decarboxylative condensation which elongates acyl-CoAs by 2C
enzymes involved in FA biosynthesis
elongation: Acetyl-CoA carboxylase + FA synthase
reduction: ketoreductase
dehydration: dehydratase
reduction: enol reductase
beta-ox vs biosynthesis
CoA vs ACP carrier
FAD/NAD+ vs NADPH reducing power
mito-matrix vs cytoplasm
where does elongation occur for fatty acids longer than 16C
mitochondria + ER
enzymes catalysing desaturation of FAs
fatty acyl-CoA desaturases
add double bonds
which enzyme catalyses the initial step of beta oxidation
Acyl-CoA dehydrogenase
acyl-CoA dehydrogenases
short chain = <6C
medium chain = 6 -12C
long chain = 13 - 21C
v.long chain = >22C
MCADD
medium chain acyl CoA dehydrogenase deficiency
auto-recessive (caucasians)
screened via heel prick test
no fasting over 10-12 hours
iv glucose if necessary
