NINJA NERD - FATTY ACID SYNTHESIS

when does does fatty acid synthesis occur

when blood glucose levels are high

what hormone stimulates fatty acid synthesis

insulin

what can also stimulate FA synthesis

high levels of ATP

STEP 1

Acetyl coA exists the membrane due to citrate being broken down into OAA and acetyl coA

this is done through the citrate lyase enzyme

NADPH is produced which is very important for FA synthesis

STEP 2

Acetyl coA carboxylase adds carbon onto acetyl coA → malonyl coA

malonyl coA can regulate CAT I/II (BOX)

What is the allosteric regulation of acetyl coA carboxylase

citrate stimulates

long chain fatty acid inhibits

what is the hormonal regulation for ACC

insulin stimulates

how is ACC activated

phosphoprotein phosphatases convert from active to inactive form of ACC (add reversible reaction)

What are the 2 components of fatty acid synthase

cysteine group with thiol

acyl carrier protein

STEP 3

Add acetyl (2C) onto ACP end using acetyl transacetylase

Transfer the 2C onto cyc group using acyl transacylase

Add on malonyl coA using malonyl transacylase onto ACP (3C - CoA gets removed)

Decarboxylation using acyl malonyl ACP condensing enzyme - removes carbon from cys group

What do we now have attached to the ACP

a beta ketone

STEP 4

Convert the beta ketone and get an OH group using the enzyme b-keto ACP reductase

NADPH is used

STEP 5

Dehydrate the molecule - remove OH group and have a double bond

using 3-hydroxyacyl dehydratase

we now have an enol

STEP 6

Get rid of double bond in the enol by reducing it using NADPH and enoyl ACP reductase

STEP 7

Using acyl transacylase we move the 4C on the ACP end and add it onto the cys end

this opens up the ACP for us to add malonyl coA - process repeats from there

we add on 2C at a time