Acute Intermittent Porphyria (15:10) is actually a deficiency in PBG deaminase. : Uroporphyrinogen III synthase deficiency is associated with Gunther's disease.
In Harper's it said that the Uroporphyrinogen 1 synthase is the one that is also called as porphobilinogen deaminase or hydroxymethylbilane synthase. Not Uroporphyrinogen 3 synthase. :)
And after Porphobilinogen, you need Uroporphyrinogen 1 synthase to form Hydroxymethylbilane then that's when you'll need a uroporphyrinogen 3 synthase to form Uroporphyrinogen 3 then etc.
So the implications for how the porphyrias manifest must be vast. you also need Cyp450s for glucocorticoid and mineralcorticoids, vitamin d and cholesterol sythesis. My question is "do different cyp450s have different purposes and if so is it possible for one function to remain while other function be affected. For example, is it possible to maintain xenobiotic metabolic function and lose the synthesis of cortisol. Can porphyria cause addisons?
Thanks a lot 4 your very good lecture. however, just one concern, isn't Porphobilinogen first catabolised into HYDROXYMETHILANE using porphobilinogen deaminase before it is converted into Uroporphyrinogen III? Need that clarity
How alcohol affects heme synthesis?? so if there is a cytochrome demand there will be increased heme synthesis which will lead to porphyrias without proper feed back inhibition or it will lead to anemia due to excess heme consumption for cytochrome synthesis??
Can I clarify- it's uroporphyrin I (from uroporphyrinogen III--> uroporphyrinogen I --> uroporphyrin I) that's responsible for the urine colouration upon sun exposure and oxidation and not uroporphyrinogen III? That's why both congenital erythropoietic porphyria and PCT have the tea coloured urine on sun exposure?
I just need clarification on something. Isn't acute intermittent porphyria due to the deficiency in hydroxymethylbilane synthase? and defective uroporphyrinogen III causes congenital erythropoietic porphyria? I noticed that you skipped the hydroxymethylbilane step and the protoporphyrinogen step.
Erythropoietic porphyria is not a high yield subject. It's very rare. That's why it was skipped here. Anyway, it results from ferrochelatase deficiency that would lead to Protoporphyrin accumulation. The other prior intermediate metabolites will also be high here. These include coproporphyrinogen and uroporphyrinogen. We know that uroporphyrinogen is photoactive. We know that it gets deposited in the skin and gives cutaneous symptoms (photosensitive blisters). Therefore, erythropoietic porphyria will present in the same way as Porphyria Cutanea Tarde ( cutaneous presentation). However, in Porphyria Cutanea Tarde, the plasma level of Protoporphyrin and Coprporpynogen is normal, while in erythropoietic porphyria they're both high. Uroporphyrinogen is high in both erythropoietic porphyrias and in Porphyria cutanea tarde and its responsible for both diseases' symptoms. So, whenever you have a presentation typical of porphyria cutanea tarde ( photosensitive blisters), don't order plasma uroporphyrinogen only, but also order coproporphyrinogen and protoporpyhin to exclude erythropoietic porphyria too.
Uroporphyrinogen III Synthase deficiency will lead to Gunther Disease "congenital erythropoietic porphyria", While a deficiency in Porphobilinogen Deaminase will lead to AIP
thanks ,,,,, but if you can draw the big whole bicture of heme glubulin .....and the steriochemestry of all that beside the chimical reaction principles involved in that all,,,,,,, beside the abnormalities ,,,, it well be great work .... thanks again
Glucose circulling in the blood stream strigers the liberation of insulin. Insulin binds to its receptors and couses the desfosforilation of the ezime ala synthase lowering max velocity of the enzime.
3. Disorderses of heme synthesis. a) Porphyrias are a group of rare inherited disorders resulting from deficiencies of enzymes in the pathway for heme biosynthesis. Six major types of porphyria have been described. Indicate the classification of porphyrias. How can we diagnose a specific type of porphyria? b) Intermediates of the pathway (ALA, porphobilinogen or porphyrinogens) accumulate and may have toxic effects on the nervous system that cause neuropsychiatric symptoms. Explain why a deficiency of enzymes of heme synthesis results in the formation of excessive quantities of heme precursors. c) When porphyrinogens accumulate, they may be converted by light to porphyrins, which react with molecular oxygen to form oxygen radicals. These radicals may cause severe damage to the skin. Thus, individuals with excessive production of porphyrins are photosensitive. Deficiency of what enzymes of heme synthesis do not result in photosensitivity but cause abdominal pain and neuropsychiatric symptoms? d) Acute attacks of porphyria can be precipitated by many drugs such as barbiturates. Explain why. e) Pyridoxine (vitamin B6) deficiencies are often associated with a microcytic, hypochromic anemia. Why would a B6 deficiency result in slow synthesis of heme and anemia?
Avhishek Ghosh First two questions are answered in the video. C) The early precursors including ALA and PBG (steps before light-sensitive uroporphyrinogen 3) D) Barbiturates are p450 inducers. E) Vitamin B6 is a prosthetic cofactor in the rate limiting step.
I love all of your videos, but I can't read your writing! It was difficult before you switched from the white board...but now its worse. I'll still keep watching, but neater writing/organization would SIGNIFICANTLY improve the videos! Thanks!!! :)
I always come to your video first to get a good overall picture.
you make it so simple
thank you!
Good job! It's an excellent lecture, which not only gives the basic mechanism, but also links to the clinical differential diagnosis! Thanks a lot!
Such a great video !!
Made it really simple and enjoyable!
Thanks alot
Such a wonderful video! Thanks! Nice and simplified! Keep up the good work! It really helped!
thank you so much for making this topic easier for me!! you are officially my hero now 😊
Very well done! Thank you very much.
I'm in a capstone course for biochemistry and this is exactly what I needed before my final!
Thanks a lot.. Tomorrow is my test and I needed this kind of vedio for it!!.. You even covered the disorders.. Thanks for helping!!..👍👍
i totally enjoyed this video ..thank u so much
reall well explained would like to see more :) keep it up
great video, very helpful, thank you
Great video!
this was very helpful. I understand everything better.
very well done!! thanks a million!!
Thank you!!! It finally makes sense!!
thank you Sir for making it so easy and simple.
Seriously seriously seriously good man. Subscribed
your video is really awesome. like really really awesome! THANK YOU!
Thanks a lot ! im a first year med student ! and this video completely eased up a chapter for me ! im totally subscribe-ing now !
Thanks again ♥
I like the way you explained Thank you
awesome, hopeing for more lectures ,thanks
absolutely wanna stick with u in the future!!!
Was of great help...good job:)
this is great, thank you!
good jobs as usual
Thanks, this video helped me a lot!
that was really helpful! thanks a lot
Love it, you´re great
i don't know how can i thank you! so helpful !
awesome, hopeing for more lectures
I liked the way you explaind it
This is dope. Thanks
It contains heme synthesis and enzyme deficiency disease. Very helpful. Thank you.
Thanks your video Helped me alot
Thank you! helped a lot! :D
Thanks a lot it was a great lecture
good job!
Awesome explanation...! Really helped me a lot.! (Y)
Awesome!
Awesome !!!!!
Thank you so much!
Very helpful ✨
Does anyone know what the other video is where he talks about alcohol inducing heme synthesis?
awesome!
THANKYOU! Subscribed 💃
Thank you so much !👌👌👍
cool learnt alot
Acute Intermittent Porphyria (15:10) is actually a deficiency in PBG deaminase. : Uroporphyrinogen III synthase deficiency is associated with Gunther's disease.
Thanks a lot !!
In Harper's it said that the Uroporphyrinogen 1 synthase is the one that is also called as porphobilinogen deaminase or hydroxymethylbilane synthase. Not Uroporphyrinogen 3 synthase. :)
Sier Salazar hey
Are u a med student?
And after Porphobilinogen, you need Uroporphyrinogen 1 synthase to form Hydroxymethylbilane then that's when you'll need a uroporphyrinogen 3 synthase to form Uroporphyrinogen 3 then etc.
Came for the learning, subbed for the humour
you are awesome
Thanks 🌹🌹🌹
So the implications for how the porphyrias manifest must be vast. you also need Cyp450s for glucocorticoid and mineralcorticoids, vitamin d and cholesterol sythesis. My question is "do different cyp450s have different purposes and if so is it possible for one function to remain while other function be affected. For example, is it possible to maintain xenobiotic metabolic function and lose the synthesis of cortisol. Can porphyria cause addisons?
acute intermittent porphyria is bcoz of PBG deaminase defeciency
UPG iii co synthase defeciency leads to congenital erythropoietic porphyria
thank you so much :)
Thanks a lot 4 your very good lecture. however, just one concern, isn't Porphobilinogen first catabolised into HYDROXYMETHILANE using porphobilinogen deaminase before it is converted into Uroporphyrinogen III? Need that clarity
it's hydroxymethylbilane
Aboda Noah yes u r right here this step is missing
How alcohol affects heme synthesis?? so if there is a cytochrome demand there will be increased heme synthesis which will lead to porphyrias without proper feed back inhibition or it will lead to anemia due to excess heme consumption for cytochrome synthesis??
Can I clarify- it's uroporphyrin I (from uroporphyrinogen III--> uroporphyrinogen I --> uroporphyrin I) that's responsible for the urine colouration upon sun exposure and oxidation and not uroporphyrinogen III? That's why both congenital erythropoietic porphyria and PCT have the tea coloured urine on sun exposure?
thumbs up!!!
I just need clarification on something. Isn't acute intermittent porphyria due to the deficiency in hydroxymethylbilane synthase? and defective uroporphyrinogen III causes congenital erythropoietic porphyria? I noticed that you skipped the hydroxymethylbilane step and the protoporphyrinogen step.
Erythropoietic porphyria is not a high yield subject. It's very rare. That's why it was skipped here. Anyway, it results from ferrochelatase deficiency that would lead to Protoporphyrin accumulation. The other prior intermediate metabolites will also be high here. These include coproporphyrinogen and uroporphyrinogen. We know that uroporphyrinogen is photoactive. We know that it gets deposited in the skin and gives cutaneous symptoms (photosensitive blisters). Therefore, erythropoietic porphyria will present in the same way as Porphyria Cutanea Tarde ( cutaneous presentation). However, in Porphyria Cutanea Tarde, the plasma level of Protoporphyrin and Coprporpynogen is normal, while in erythropoietic porphyria they're both high. Uroporphyrinogen is high in both erythropoietic porphyrias and in Porphyria cutanea tarde and its responsible for both diseases' symptoms. So, whenever you have a presentation typical of porphyria cutanea tarde ( photosensitive blisters), don't order plasma uroporphyrinogen only, but also order coproporphyrinogen and protoporpyhin to exclude erythropoietic porphyria too.
Uroporphyrinogen III Synthase deficiency will lead to Gunther Disease "congenital erythropoietic porphyria",
While a deficiency in Porphobilinogen Deaminase will lead to AIP
Great :)
thank you very much :) but can u also show how heme is degraded...
thanks ,,,,, but if you can draw the big whole bicture of heme glubulin .....and the steriochemestry of all that beside the chimical reaction principles involved in that all,,,,,,, beside the abnormalities ,,,, it well be great work .... thanks again
Hm it's so cool, but do you have any lection about vitamin B12 and folic acid metabolic disorders? :P
Thanks
If you could elaborate porphyria in depth
please can u give lecture about degradation oh heme.
thanks
thanq :)
greattttttttttt
It's ALA dehyratase not hydogenase
No structure.here in Nigeria they demand structure especially university of Ibadan
ALA "dehydratase" not "dehydrogenase".
anyway thanks for d much helpful video
navjot singh yes the same was i thinking
thanks
it's true that glucose repress heme synthesis, can you help me and explain how does it work? thanks a lot, your video was really helpful
Glucose circulling in the blood stream strigers the liberation of insulin. Insulin binds to its receptors and couses the desfosforilation of the ezime ala synthase lowering max velocity of the enzime.
wow!
Prophobilingen is converted to OH-methylbilane by tge enzyme ( prophobilinogen deaminase ) 😊
U miss this step ..
Anyway it's helpful
can u make a quick vid about heme degredation plz its an emergency
thanks help me for my final !!
You didn't talk at all about Eyrthropoietic Protoporphyria (EPP) which is the third most common Porphyria disease.
as long as it takes out two molecules of water, shouldn't "ALA DH" be called ALA dehydrase?
it's ferrochelatase right??
yup
Yes😊
expalination for alcohol is very good
drug inducing p450 example is barbiturates
👏
PBG deaminase and uroporphyrinogen 111 synthase are different enzymes
Awesome Barney style.
where are hydroxymethylbillane and protoporphobilinogen 9
Ego! yeaaa
It is FERROCHELOTASE, not ferrochetalase.
Þórður Gunnar Þorvaldsson Both are right.
3. Disorderses of heme synthesis.
a) Porphyrias are a group of rare inherited disorders resulting from deficiencies of enzymes in the pathway for heme biosynthesis. Six major types of porphyria have been described. Indicate the classification of porphyrias. How can we diagnose a specific type of porphyria?
b) Intermediates of the pathway (ALA, porphobilinogen or porphyrinogens) accumulate and may have toxic effects on the nervous system that cause neuropsychiatric symptoms. Explain why a deficiency of enzymes of heme synthesis results in the formation of excessive quantities of heme precursors.
c) When porphyrinogens accumulate, they may be converted by light to porphyrins, which react with molecular oxygen to form oxygen radicals. These radicals may cause severe damage to the skin. Thus, individuals with excessive production of porphyrins are photosensitive. Deficiency of what enzymes of heme synthesis do not result in photosensitivity but cause abdominal pain and neuropsychiatric symptoms?
d) Acute attacks of porphyria can be precipitated by many drugs such as barbiturates. Explain why.
e) Pyridoxine (vitamin B6) deficiencies are often associated with a microcytic, hypochromic anemia. Why would a B6 deficiency result in slow synthesis of heme and anemia?
Avhishek Ghosh
First two questions are answered in the video.
C) The early precursors including ALA and PBG (steps before light-sensitive uroporphyrinogen 3)
D) Barbiturates are p450 inducers.
E) Vitamin B6 is a prosthetic cofactor in the rate limiting step.
No defense Mr, I think you need scripts for the lecture as the others do :)
its not ferro chetalase ,its ferro chelatase
it not dehydrogenase but ALA dehydratase
y is this lasting 22 mins.
good .sir pls! typing can be improved.very helpful to post graduate cources.
It's actually coproporphyrinogen, not coporphyrinogen and it's ferrochelatase not ferrochetalase. :)
Thanks for the video though :)
Ferrochelatase, not ferrochetalase.
I love all of your videos, but I can't read your writing! It was difficult before you switched from the white board...but now its worse. I'll still keep watching, but neater writing/organization would SIGNIFICANTLY improve the videos! Thanks!!! :)
its is FERROCHELATASE..... OR HEME SYNTHASE... your calling it ferrochetalase throughout the video !!!
Unfortunatly you left 2 steps out.