BIOSYNTHESIS OF HEME --- MNEMONICS

Heme synthesis mnemonic

1. The heme ring system is synthesized from glycine and succinyl-CoA in the mitochondria.
d-Aminolevulinate Synthase (ALA Synthase, ALAS) is the rate-limiting step. Pyridoxal phosphate is the coenzyme.

Mnemonic: "Alas! Mighty dracula sucks blood with glistening phoshorous teeth."
Alas! (ALA synthetase enzyme)
Mighty (Mitochondria)
Dracula (d-ALA)
Sucking (Succinyl CoA)
Blood (Heme synthesis)
Glistening (Glycine)
Phosphorous (Pyridoxal phosphate coenzyme)

2. PBG Synthase (Porphobilinogen Synthase), also called ALA Dehydratase, catalyzes condensation of two molecules of d-aminolevulinic acid (ALA) to form porphobilinogen (PBG). This step is inhibited by lead.

Mnemonic: "This leads to dehydration of poor Billy."
Leads (Pb inhibits this step)
To (Two molecules of d-ALA)
Dehydration (ALA dehydratase)
Poor Billy (Porphobilinogen)

3. After that, I remember "UCP" (UnCouplers of oxidative phosphorylation) for the next three substrates:

Uroporphyrinogen
Coproporphyrinogen
Protoporphyrinogen

(Alternatively: "Urine, crap, poop")

4. Protoporphyrinogen is acted upon by Ferrochelatase which incorporates iron to produce heme. 

Mnemonic: "PharoaH"
P: Protoporphyrinogen
H: Heme
Pharoah sounds like "Ferro" for Ferrochelatase

This step is inhibited by lead too. 

Mnemonic: "Latase Likes Lead. "

HERE ARE A FEW NOTES REGARDING HEME SYNTHESIS:-

What the short forms in the notes stand for -
AIP: Acute Intermittent Porphyria
CEP: Congenital erythropoietic protoporphyria
PCT: Porphyria cutanea tarda
HCP: Hereditary coproporphyria
VP: Varlegate porphyria
EPP: Erythropoietic protoporphyria

That's all!