Making Heme Flashcards
What kind of side chain groups are added on to the pyrrole ring structure?
methyl
acetate
propionate
vinyl chemical groups
which of the porphyrins do no coordinate a metal ion?
the phycobilins found in red algae and in cyanobacteria
which of the porphyins coordinate Mg ions?
the Cholrophylls
which of the porphrins coordinate Fe?
Heme which is in, hemoglobin, myoglobin, CP450,
which of the porphyrins coorddinate Co?
the Cobalamins like Vitamin B12
Where are the Nitrogens in Heme taken from?
Gylcine
how many red blood cells are degraded per hour?
100/200 Million Red blood Cells
What is the only mammalian tissue that does not make heme?
the Mature Red Blood cells
where does the most Heme synthesis happen?
in the erythroid tissue this tissue is made up of cells in the bone marrow that are red blood cell producing also there is a lot of heme synthesis happening in the liver
why is there different regulation of Heme synthesis between the liver and the bone marrow?
all of the heme being made in the bone is for making hemoglobin whereas in the the liver the Heme is for other things like Cytochrome P450
How is Fe stored and transported in the body?
1: the Fe travel in the blood through binding to apotransferrin after being absorbed by the duodenum around 1-2mg per day
2: The Fe Transferrin complex is engulfed in receptor mediated endocytosis
3: the Fe is separated and stored as ferritin in the bone marrow
4: The receptor and the apotransferrin are then recycled back to the cell membrane to be used again
which reactions in the Heme synthesis pathway happen in the Mt?
the first reaction and the last three reactions
what is the first reaction in the Heme synthesis pathway dependant on?
Vitamin B6
what does it mean if something has the suffix ogen?
these are reduced precursor forms of Heme
Is anaemia a main symptom of porphyria?
No. Heme is still synthesised in adequate quantities
Which drugs increase the demand for Heme?
barbiturates sulfur drugs antifungals/hypertensives retroviral drugs vasodilators oral contraceptives
in what three ways does Heme affect the production of ALAS1?
it affects the promotor for ALAS one
leading
to impaired transcription, destabilises the mRNA and the protein of ALAS 1
reduced translocation to the mt from the cytosol
and direct inhbition of ALAS 1
fasting also activated a transcrptional co activator of ALAS1 increasing the amount of ALAS1
how is ALAS 2 controlled?
by coordinating Heme synthesis with globin synthesis
what other enzymes are condtroleld in erythroid tissue?
uroporphyrinogen cosynthase
and ferrochelatase
what else may influence Heme synthesis?
drugs and the circadian clock
