Three Clinically Significant Forms of Porphyrins 1. Found in urine and is most stable in water 2. Found in urine, stool, and blood 3. Found in stool

1. Uroporphyrin 2. Coproporphyrin 3. Protoporphyrin

Pathway of Heme Synthesis 1. The ____ and ____ are the main sites of heme synthesis 2. The conversion of one product to another through enzymatic action happens ____ the cell 3. Reduced enzymatic activity results in excess production of one or more ____ substances

1. Liver and Bone Marrow 2. Inside 3. Precursor

Pathway of Heme Synthesis 1. ____ and ____ are present in the mitochondria and will serve as raw materials for heme synthesis 2. The 2 raw materials will be acted upon by ____ to produce ____

1. Glycine and Succinyl-CoA 2. ALA synthase; δ-aminolevulinic acid (ALA)

Pathway of Heme Synthesis 1. As δ-aminolevulinic acid (ALA) is produced, it will be acted upon by ____ therefore producing ____ 2. ____ molecules of ALA will produce ____ molecules of the new product

1. ALA dehydratase; Porphobilinogen (PBG) 2. (2) for ALA and (4) for PBG

Pathway of Heme Synthesis 1. The PBG will be acted upon by ____ to produce ____ which is a linear tetrapyrrole 2. The new product will now be the substrate of ____ in producing ____

1. Uroporphyrinogen-I Synthase; Hydroxymethylbilane 2. Uroporphyrinogen-III Co-Synthase; Uroporphyrinogen-III Note: Uroporphyrinogen-I Synthase is aka Hydroxymethylbilane Synthase

Pathway of Heme Synthesis 1. Hydroxymethylbilane will be spontaneously acted upon by a specific enzyme to produce ____ 2. As Uropophyrinogen-III is being produced, it will be acted upon by ____ to produce ____

1. Uroporphyrinogen-I 2. Uroporphyrinogen carboxylase; Coproporphyrinogen-III

Pathway of Heme Synthesis 1. As Coproporphyrinogen-III is produced, it will be acted upon by ____ to produce ____ 2. The new product will then by acted upon by ____ to produce ____

1. Coproporphyrinogen oxidase; Protoporphyrinogen-III 2. Protoporphyrinogen oxidase; Protoporphyrin III Note: Protoporphyrin III is aka Protoporphyrin IX

(P) Lec 3: Porphyrins (Part 2) Flashcards by Kchianna Lauren Coronel

These are metabolic intermediates in the hemoglobin, myoglobin, and cytochrome synthesis
It produces a red-violet to red-brown color
These will not increase unless there is a problem with heme synthesis

Porphyrins

How well did you know this?

Not at all

Perfectly

This molecule is composed of heme and globin

Hemoglobin

How well did you know this?

Not at all

Perfectly

This molecule is composed of iron and a protoporphyrin ring
This also incorporates into a protein (globin) to produce a biologically functional hemoprotein (hemoglobin)

Heme

How well did you know this?

Not at all

Perfectly

Three Clinically Significant Forms of Porphyrins

Found in urine and is most stable in water
Found in urine, stool, and blood
Found in stool

Uroporphyrin
Coproporphyrin
Protoporphyrin

How well did you know this?

Not at all

Perfectly

The three forms of porphyrins (Uroporphyrin, Coproporphyrin, Protoporphyrin) are found within the biological ____ produced by the body

Fluids

Note: Increased levels in body fluids indicate abnormal heme synthesis

How well did you know this?

Not at all

Perfectly

Most porphyrins in the body are present in this form
This is a functional form of the compound that must be used in heme synthesis
Are believed to be colorless, unstable, and do not fluoresce

Porphyrinogens

How well did you know this?

Not at all

Perfectly

Initially, porphyrins are in the form of ____
It will be converted to porphyrins for heme synthesis when they are ____ in the body

Porphyrinogens
Oxidized

How well did you know this?

Not at all

Perfectly

In cases wherein a sample contains porphyrinogens upon excretion, when they are exposed to ____, the porphyrinogens will be converted to porphyrin

Air

How well did you know this?

Not at all

Perfectly

Pathway of Heme Synthesis

The ____ and ____ are the main sites of heme synthesis
The conversion of one product to another through enzymatic action happens ____ the cell
Reduced enzymatic activity results in excess production of one or more ____ substances

Liver and Bone Marrow
Inside
Precursor

How well did you know this?

Not at all

Perfectly

Pathway of Heme Synthesis

____ and ____ are present in the mitochondria and will serve as raw materials for heme synthesis
The 2 raw materials will be acted upon by ____ to produce ____

Glycine and Succinyl-CoA
ALA synthase; δ-aminolevulinic acid (ALA)

How well did you know this?

Not at all

Perfectly

Pathway of Heme Synthesis

As δ-aminolevulinic acid (ALA) is produced, it will be acted upon by ____ therefore producing ____
____ molecules of ALA will produce ____ molecules of the new product

ALA dehydratase; Porphobilinogen (PBG)
(2) for ALA and (4) for PBG

How well did you know this?

Not at all

Perfectly

Pathway of Heme Synthesis

The PBG will be acted upon by ____ to produce ____ which is a linear tetrapyrrole
The new product will now be the substrate of ____ in producing ____

Uroporphyrinogen-I Synthase; Hydroxymethylbilane
Uroporphyrinogen-III Co-Synthase; Uroporphyrinogen-III

Note: Uroporphyrinogen-I Synthase is aka Hydroxymethylbilane Synthase

How well did you know this?

Not at all

Perfectly

Pathway of Heme Synthesis

Hydroxymethylbilane will be spontaneously acted upon by a specific enzyme to produce ____
As Uropophyrinogen-III is being produced, it will be acted upon by ____ to produce ____

Uroporphyrinogen-I
Uroporphyrinogen carboxylase; Coproporphyrinogen-III

How well did you know this?

Not at all

Perfectly

Pathway of Heme Synthesis

As Coproporphyrinogen-III is produced, it will be acted upon by ____ to produce ____
The new product will then by acted upon by ____ to produce ____

Coproporphyrinogen oxidase; Protoporphyrinogen-III
Protoporphyrinogen oxidase; Protoporphyrin III

Note: Protoporphyrin III is aka Protoporphyrin IX

How well did you know this?

Not at all

Perfectly

Pathway of Heme Synthesis

The Protoporphyrin ring IX will be acted upon by ____ producing your heme

Ferrochelatase (heme synthase)

How well did you know this?

Not at all

Perfectly

Pathway of Heme Synthesis

Heme, protoporphyrin IX, protoporphyrinogen IX, and the conversion of glycine + succinyl-CoA to delta aminolevulinic acid happens where?

In the mitochondria (because the process needs energy)

How well did you know this?

Not at all

Perfectly

Pathway of Heme Synthesis

The conversion that happens from delta-aminolevulinic acid to coproporphyrinogen happens where?

Cytoplasm (it needs less energy than those processes that occur in the mitochondria)

How well did you know this?

Not at all

Perfectly

In the heme synthesis pathway, it can also relate to ____ because this targets heme synthesis, specifically ALA dehydratase and ferrochelatase

Lead poisoning/ Presence of Lead

How well did you know this?

Not at all

Perfectly

A deficiency of one enzyme involved in the heme synthesis pathway will lead to porphyria EXCEPT for what enzyme?

ALA Synthase

How well did you know this?

Not at all

Perfectly

If the deficiency of ALA Synthase does not lead to porphyria, what does it result to?

Sideroblastic Anemia

How well did you know this?

Not at all

Perfectly

Refers to conditions wherein there is an aberration or disturbance in heme synthesis leading to the accumulation of porphyrins
A group of rare, inherited, or acquired metabolic disorders caused by a loss or gain of function and a mutation in the enzymes responsible for heme biosynthesis

Porphyria

How well did you know this?

Not at all

Perfectly

Types of Porphyria

Refers to the overproduction of heme precursors in the 1.) liver and 2.) bone marrow

Hepatoerythropoietic Porphyria (HEP)
Erythropoietic Porphyria (EP)

How well did you know this?

Not at all

Perfectly

Types of Porphyria

These 2 types are the only acquired ones while the rest are all inherited

Plumboporphyria (PP)
Porphyria Cutanea Tarda (PCT)

How well did you know this?

Not at all

Perfectly

The ending of all these types of porphyrias is that there is always an overproduction, accumulation, and excretion of toxic ____ compounds and porphyrins

Precursor

How well did you know this?

Not at all

Perfectly

# Symptoms of Porphyria - Manifestations include abdominal pain, vomiting, constipation, tachycardia, hypertension, etc. - Plumboporphyria (PP) and Acute Intermittent Porphyria (AIP) present with this type of symptom

Neurologic/Neuropsychiatric

# Symptoms of Porphyria - Manifestations include photosensitivity (most usual presenting symptom), blisters, facial hair, and hyperpigmentation - Congenital Erythropoietic Porphyria (CEP), Porphyria Cutanea Tarda (PCT), Hepatoerythropoietic Porphyria (HEP), and Erythropoietic Porphyria (EP) present with this type of symptom

Cutaneous

# Symptoms of Porphyria - Includes both neurologic/neuropsychiatric and cutaneous manifestations - Hereditary Coproporphyria (HCP) and Variegate Protoporphyria (VP) present with this type of symptom

Neurocutaneous

# Symptoms of Porphyria Give the porphyrias associated with this symptom: Neurologic/ Neuropsychiatric

1. Plumboporphyria (PP) 2. Acute Intermittent Porphyria (AIP)

# Symptoms of Porphyria Give the porphyrias associated with this symptom: Cutaneous

1. Congenital Erythropoietic Porphyria (CEP) 2. Porphyria Cutanea Tarda (PCT) 3. Hepatoerythropoietic Porphyria (HEP) 4. Erythropoietic Porphyria (EP)

# Symptoms of Porphyria Give the porphyrias associated with this symptom: Neurocutaneous

1. Hereditary Coproporphyria (HCP) 2. Variegate Protoporphyria (VP)

# Types of Porphyria There is increased aminolevulinic acid (ALA) and porphobilinogen (PBG) in urine producing a black or red color but turns dark brown upon exposure to air or light

1. Plumboporphyria (PP) 2. Acute Intermittent Porphyria (AIP) | Note: The porphyrias that present with neurologic symptoms

# Types of Porphyria In Plumboporphyria (PP) and Acute Intermittent Porphyria (AIP), what 2 substances give the characteristic red and black color of urine respectively?

- Red: Porphyrin - Black: Porphobilin

# Types of Porphyria - Is aka ALA-dehydratase (ALAD) deficiency porphyria - Lead and ferrochelatase are inhibitors to ALAD - There is increased urine aminolevulinic acid (ALA) but with normal excretion of porphobilinogen (PBG)

Plumboporphyria (PB)

# Types of Porphyria - Dithiothreitol or sulfhydryl reagent is used to differentiate this type with lead poisoning - It is sometimes mistaken for lead poisoning due to a similar presentation of increased ALA

Plumboporphyria (PB)

# Types of Porphyria In Plumboporphyria (PB) testing, if you add the dithiothreitol or sulfhydryl reagent and the ALA increases, what does it mean?

(+) for Plumboporphyria (PB)

# Types of Porphyria In Plumboporphyria (PB) testing, if the ALA in urine is increased at first but then turns normal upon the addition of the dithiothreitol or sulfhydryl reagent, what does it mean?

(+) for Lead Poisoning

# Types of Porphyria The enzyme deficient in this condition is the porphobilinogen deaminase or hydroxymethylbilane synthase/uroporphyrinogen-I-synthase

Acute Intermittent Porphyria (AIP)

# Types of Porphyria - The rarest among all porphyrias and is also the most severe - The enzyme deficient is Uroporphyrinogen III cosynthase (Gunther's disease)

Congenital Erythropoietic Porphyria (CEP)

# Types of Porphyria - There is an increase of uroporphyrin and coproporphyrin in urine and stool - The teeth fluoresce red (erythrodontia) under UV light due to the deposition of porphyrin in the dentin - Manifestations are seen as early in infants - Infants produce red to brown urine and exhibit cutaneous photosensitivity (usual symptom)

Congenital Erythropoietic Porphyria (CEP)

# Types of Porphyria - The enzyme deficient is Uroporphyrinogen decarboxylase - The most common porphyria - Manifested by having blisters and fragility in light-exposed skin due to free radicals present in the skin leading to oxidative damage

Porphyria Cutanea Tarda (PCT)

# Types of Porphyria - Liver damage is also possible because of iron depletion - There is abnormal growth of hair present - There's increased isocoproporphyrin and uroporphyrin in the patient's biologic fluids

Porphyria Cutanea Tarda (PCT)

# Types of Porphyria Types of Porphyria Cutanea Tarda (PCT): 1. Deficiency of the enzyme is restricted to liver 2. Deficiency of the enzyme is present in all tissues

1. Type 1 PCT 2. Type 2 PCT

# Types of Porphyria - The enzyme that is deficient is Uroporphyrinogen decarboxylase (reduced activity of 90% and more) - Affects both the liver and bone marrow - Photosensitivity begins in childhood

Hepatoerythropoietic Porphyria (HEP)

# Types of Porphyria - Hepatic diseases are common and present later on - There is presence of abnormal/excess facial hair and scarring (blisters) of the hands and face - There is increased isocoproporphyrin, uroporphyrin, and zinc protoporphyrin (ZPP)

Hepatoerythropoietic Porphyria (HEP)

# Types of Porphyria - The enzyme deficient is ferrochelatase - It is the second most common porphyria - Manifested as burning of light-exposed skin

Erythropoietic Porphyria (EP)

# Types of Porphyria - There is increased free erythrocyte protoporphyrin (FEP) and Zn protoporphyrin in RBC, plasma, and stool because iron is not incorporated in the RBC - Symptoms include photosensitivity, burning, itching, pain in the skin, excessive hair growth, and liver disease

Erythropoietic Porphyria (EP)

# Types of Porphyria - The enzyme deficient is coproporphyrinogen oxidase - The hallmark is increased coproporphyrin in stool (sometimes in urine) - There is increased ALA and PBG - Harderoporphyria is a rare erythropoietic form of it

Hereditary Coproporphyria (HCP)

# Types of Porphyria - Aka South African porphyria - The enzyme deficient is protoporphyrinogen oxidase - Its manifestations are the same with Acute Intermittent Porphyria (AIP) - The hallmark is increased protoporphyrin and coproporphyrin in stool

Variegate Protoporphyria (VP)

# Types of Porphyria - These are aka porphyrinurias wherein there is an increased excretion of urinary porphyrins - It is not a defect in the biochemical synthesis of heme but a result of conditions such as toxins and drugs

Secondary Porphyrias

# Types of Porphyria Regular or Secondary porphyrias? 1. Increased ALA and porphobilinogen in urine and other body fluids 2. Increased ALA but with normal porphobilinogen in urine

1. Regular porphyria 2. Secondary porphyria

# Treatment If a patient suffers from porphyria of the cutaneous type, they should avoid what?

Sunlight

# Treatment This can be given for a hematin limit synthesis of porphyrins in the cells of the bone marrow

Hematin

# Treatment Decrease the heme load by having therapeutic ____ or giving ____ to chelate the iron present

1. Phlebotomy 2. Deferoxamine

# Laboratory Determination What 2 qualitative screening tests can be used to measure porphobilinogen (PBG) and ALA?

1. Watson-Schwartz 2. Hoesch Test

# Laboratory Determination In order to measure PBG and ALA quantitatively, what test can be performed?

Ion Exchange Column

# Laboratory Determination Between the Watson-Schwartz and Hoesch Test, what is the confirmatory test for the other one?

Hoesch Test (it confirms the result of Watson-Schwartz)

# Laboratory Determination - Porphobilinogen (PBG) forms a ____ color when mixed with ____ - It is a qualitative ____ test for the detection and differentiation of ____ and porphobilinogen - A positive result for PBG and ALA in urine is indicated by a ____ color

1. Red-orange; Ehrlich's reagent (pdab) 2. Screening; urobilinogen 3. Red-orange | Note: pdab means para-dimethylaminobenzaldehyde

# Laboratory Determination - An extraction method is done - Urine is added with Ehrlich's reagent alongside sodium acetate - If the tube turns red or pink, it is (+) for either urobilinogen or porphobilinogen - Add chloroform to determine whether urobilinogen or porphobilinogen is present - There will be a production of 2 layers afterwards

Watson-Schwartz

# Laboratory Determination In Watson-Schwartz, what do you add to differentiate urobilinogen from porphobilinogen that forms 2 layers?

Chloroform OR Butanol

# Laboratory Determination In Watson-Schwartz, the Ehrlich's reagent is added alongside what other substance to produce a red/pink color?

Sodium Acetate

# Laboratory Determination Watson-Schwartz: - The top layer is aqueous and the red/pink chloroform settled at the bottom - After adding butanol, the red/pink color is present at the top

Urobilinogen | Note: Butanol can be used if chloroform is not present

# Laboratory Determination Watson-Schwartz: - The bottom layer is aqueous and the red/pink chloroform settled at the top - After adding butanol, the red/pink color is present at the bottom | Note: Butanol can be used if chloroform is not present

Porphobilinogen

# Laboratory Determination What interfering agents sometimes act up when performing Watson-Schwartz?

Urobilinogen and Indole

# Laboratory Determination The reagent used for this test does not react with urobilinogen as this is only used to confirm the result of the other test

Hoesch Test

# Laboratory Determination What specimens (3) can be used?

1. 24H urine 2. Whole blood 3. 1g of fecal sample | Note: The 3 sources of porphyrins are urine, blood, and stool

# Laboratory Determination What is the anticoagulant of choice?

EDTA

# Specimen Considerations - Porphyrin is ____ sensitive, together with bilirubin - Store the specimen at ____ degrees Celsius for ____ hours - If not performing ASAP, store the specimen at ____ degrees Celsius

1. Light 2. 4 degrees for 48H 3. 23 degrees

# Methods - The ____ and ____ lamps are used for qualitative screening methods - Porphyrins ____ under UV light - ____ colored fluorescence indicates a (+) result

1. UV and Wood's 2. Fluoresce 3. Orange-red

# Methods - Other qualitative tests include: ____ , ____ , and ____ - An excitation wavelength is set at ____ to ____ nm - An emission wavelength is set at ____ to ____ nm

1. Fluorometry, HPLC, and HP-TLC 2. 400 to 405nm 3. 594 to 598nm

# Identify the type of porphyria ALA-D deficiency

Plumboporphyria (PB)

# Identify the type of porphyria Increased urine ALA but with the normal porphobilinogen (PBG) excretion

Plumboporphyria (PB)

# Identify the type of porphyria Dithiothreitol or sulfhydryl reagent

Plumboporphyria (PB)

# Identify the type of porphyria Porphobilinogen deaminase or Hydroxymethylbilane synthase (uroporphyrinogen-I-synthase) is deficient

Acute Intermittent Porphyria (AIP)

# Identify the type of porphyria Uroporphyrinogen III cosynthase is deficient

Congenital Erythropoietic Porphyria (CEP)

# Identify the type of porphyria Gunther's Disease

Congenital Erythropoietic Porphyria (CEP)

# Identify the type of porphyria There is increased uroporphyrin and coproporphyrin in urine and stool

Congenital Erythropoietic Porphyria (CEP)

# Identify the type of porphyria There is increased coproporphyrin in urine and stool

1. Congenital Erythropoietic Porphyria (CEP) 2. Hereditary Coproporphyria (HCP) 3. Variegate Protoporphyria (VP)

# Identify the type of porphyria There is photosensitivity

1. Congenital Erythropoietic Porphyria (CEP) 2. Porphyria Cutanea Tarda (PCT) 3. Hepatoerythropoietic Porphyria (HEP) 4. Erythropoietic Porphyria (EP)

# Identify the type of porphyria Uroporphyrinogen decarboxylase is deficient

1. Porphyria Cutanea Tarda (PCT) 2. Hepatoerythropoietic Pophyria (HEP)

# Identify the type of porphyria Liver damage/disease

1. Porphyria Cutanea Tarda (PCT) 2. Hepatoerythropoietic Porphyria (HEP) 3. Erythropoietic Porphyria (EP)

# Identify the type of porphyria Increased isocoproporphyrin, uroporphyrin, and zinc protoporphyrin (ZPP)

Hepatoerythropoietic Porphyria (HEP)

# Identify the type of porphyria Ferrochelatase is deficient

Erythropoietic Porphyria (EP)

# Identify the type of porphyria There is increased free erythrocyte protoporphyrin (FEP) and Zn protoporphyrin in RBC, plasma, and stool

Erythropoietic Porphyria (EP)

# Identify the type of porphyria Coproporphyrinogen oxidase is deficient

Hereditary Coproporphyria (HCP)

# Identify the type of porphyria Increased isocoproporphyrin and uroporphyrin

1. Porphyria Cutanea Tarda (PCT) 2. Hepatoerythropoietic Porphyria (HEP)

# Identify the type of porphyria Increased ALA and PBG

Hereditary Coproporphyria (HCP)

# Identify the type of porphyria Harderopoporphyria

Hereditary Coproporphyria (HCP)

# Identify the type of porphyria South African Porphyria

Variegate Protoporphyria (VP)

# Identify the type of porphyria Protoporphyrinogen oxidase is deficient

Variegate Protoporphyria (VP)

# Identify the type of porphyria There is increased protoporphyrin and coproporphyrin in stool

Variegate Protoporphyria (VP)