Porphyrins and Hemoglobin

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Total cards: 24•Content version: v4•Public deck•Updated: 8/1/2026

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Front (Question)

chemical intermediates of hemoglobin, myoglobin, cytochromes, and enzymes (catalase and peroxidase)

Back (Answer)

Porphyrins

Front (Question)

What causes red color of hemoglobin?

Back (Answer)

presence of alternating double bonds of porphyrins allows the structure to absorb light

Front (Question)

All porphyrins are macrocyclic structures consisting of a _________ ring linked by______ bridges.

Back (Answer)

tetrapyrrole, methyl

Front (Question)

Porphyrins also fluoresce reddish-pink at ____ nm

Back (Answer)

400

Front (Question)

Four ____ atoms chelate metal atoms (usually iron, competes with zinc) ▪ Iron chelates with protoporhyrin IX to form heme

Back (Answer)

Nitrogen

Front (Question)

Iron in heme can also bind to globin proteins to form ________ & ____________.

Back (Answer)

HEMOGLOBIN & MYOGLOBIN

Front (Question)

fights against reactive oxygen species

Back (Answer)

catalase

Front (Question)

hemoglobin, myoglobin, and cytochromes all contain…

Back (Answer)

heme

Front (Question)

Heme synthesis occurs in all cells, but primarily ____________(erythroidprecursors) and ______.

Back (Answer)

bone marrow, liver

#10

Front (Question)

Iron chelates with ________________ to form heme

Back (Answer)

protoporhyrin IX

#11

Front (Question)

Enzymes in heme synthesis localized in…

Back (Answer)

mitochondria and cytoplasm

#12

Front (Question)

what are the Mitochondrial enzymes involved with heme synthesis?

Back (Answer)

1) ALA synthase, 2) copropophyinogen oxidase, 3) protoporhyrinoghen oxidase, and 4) ferriochelatase

#13

Front (Question)

What are the Cytoplasmic enzymes involved with heme synthesis?

Back (Answer)

1) ALA dehydrogenase, 2) PBG deaminase, 3) Uroporphyrinogen III synthetase, and 4) Uroporphyrinoghen decarboxylase

#14

Front (Question)

ALA & PBG are ________soluble

Back (Answer)

water

#15

Front (Question)

precursors to porphyrins

Back (Answer)

▪ Porphyrinogens

#16

Front (Question)

these spontaneously oxidize (with light oxygen or oxidizing agents) to form three major porphyrins:

Back (Answer)

Porphyrinogens

#17

Front (Question)

three major porphyrins…

Back (Answer)

• Uroporphyrin [URO]: excreted in urine • Coproporphyrin [CORPO]: excreted in urine and/or feces • Protoporphyrin [PROTO]: excreted in feces

#18

Front (Question)

porphyrin that is excreated in urine?

Back (Answer)

Uroporphyrin [URO]

#19

Front (Question)

porphyrin excreted in urine and/or feces

Back (Answer)

Coproporphyrin [CORPO]

#20

Front (Question)

porphyrin that is excreted in feces?

Back (Answer)

Protoporphyrin [PROTO]

#21

Front (Question)

▪Porphyria can be inherited or caused by…

Back (Answer)

drugs, liver disease, anemias, or toxic metals that cause disturbances in heme synthesis and porphyrin metabolism

#22

Front (Question)

How many enzymes are involved in heme synthesis?

Back (Answer)

8 Deficiency in seven of the eight enzymes involved in heme synthesis ! Leading to a distinct form of porphyria

#23

Front (Question)

Lack of enzyme activity –> decrease in formation and excretion of porphyrin or accumulation of its __________.

Back (Answer)

precursors

#24

Front (Question)

Symptoms of Neurological porphyria?

Back (Answer)

Constipation, nausea, vomiting, severe abdominal pain, tachycardia, hypertension, sweating and urinary retention, *neurotoxicity, psychiatric disturbances, Cutaneous lesions, hyperpigmentation