topic 4

Question 1

Hb with O2

Answer 1

Oxyhemoglobin (oxyHb)

Question 2

Hb without O2

Answer 2

Deoxyhemoglobin (deoxyHb)

Question 3

contains Fe3+ instead of Fe2+ in heme groups

Answer 3

Methemoglobin (metHb)

Question 4

CO binds to Fe2+ in heme in case of CO poisoning or smoking. CO has 200x higher affinity to Fe2+ than O2.

Answer 4

Carbonylhemoglobin (HbCO)

Question 5

CO2 is non-covalently bound to globin chain of Hb. HbCO2 transports CO2 in blood (about 23%).

Answer 5

Carbaminohemoglobin (HbCO2)

Question 6

is formed spontaneously by nonenzymatic
reaction with Glc. People with DM have more HbA1c than normal (› 7%).
Measurement of blood HbA1c is useful to get info about long-term control of glycemia

Answer 6

Glycohemoglobin (HbA1c)

Question 7

are cyclic compounds that bind metal ions (usually Fe2+ or Fe3+)

Answer 7

Porphyrins

Question 8

are porphyrin precursors
intermediate between porphobilinogen & protoporphyrin
Porphobilinogen Porphyrinogens Protoporphyrins

Answer 8

Porphyrinogens

Question 9

• are hereditary or acquired disturbances of heme synthesis
• in all cases there is an identifiable abnormality of the enzymes which synthesize heme

Answer 9

PORPHYRIAS - DISTURBANCES OF HEME SYNTHESIS

Question 10

are rare inherited defects in heme synthesis.
● An inherited defect in an enzyme of heme synthesis results in accumulation of one or more of porphyrin precursors depending on location of block of the heme synthesis pathway.

Answer 10

PORPHYRIAS

Question 11

▶ Chronic hepatic porphyria
▶ The most common type of porphyria
▶ a deficiency in uroporphyrinogen decarboxylase
▶ Clinical expression of the enzyme deficiency is influenced by various
factors, such as exposure to sunlight, the presence of hepatitis B or C
▶ Clinical onset is during the fourth or fifth decade of life.
▶ Porphyrin accumulation leads to cutaneous symptoms and urine

Answer 11

PORPHYRIA CUTANEA TARDA

Question 12

Porphyrias leading to accumulation of ALA and porphobilinogen cause abdominal pain and neuropsychiatric disturbances, ranging from anxiety to delirium.

Answer 12

Acute Intermittent Porphyria

Question 13

often precipitated by administration of drugs such as barbiturates and ethanol.

Answer 13

ACUTE HEPATIC PORPHYRIAS

Question 14

most serious case of porphyria - very rare

Answer 14

Congenital Erythropoeitic Porphyria

Question 15

is a hemoprotein only found in the cytoplasm of (ery) transports O2 and CO2 between lungs and vario

Answer 15

HEMOGLOBIN (HB)

Question 16

STRUCTURE OF HEMOGLOBIN

Answer 16

spherical molecule consisting of 4 peptide subunits (globins) = quartenary structure

Question 17

• is a single-chain globular protein of 153 AA, containing 1 heme group
• transports O2 in skeletal and heart muscle
• is found in cytosol within cells
• is a marker of myocard damage

Answer 17

MYOGLOBIN (MB)

Question 18

• synthesis of heme starts in mitochondria
• succinyl-CoA and Gly undergo a condensation → ALA
• reaction is catalyzed by enzyme ALA synthase

Answer 18

Δ-AMINOLEVULINIC ACID (ALA)

Question 19

• oxidation of protoporphyrinogen IX produces the conjugated π- electrone system of protoporphyrin IX

Answer 19

PROTOPORPHYRINOGEN IX → PROTOPORPHYRIN IX

Question 20

is a key regulatory enzyme

Answer 20

ALA synthase

Question 21

the major form of Hb in adults and in children over 7 months.

Answer 21

HbA1

Question 22

is a minor form of Hb in adults. It forms only 2 – 3% of a total Hb A.

Answer 22

HbA2 (2 α, 2 δ)

Question 23

in fetus and newborn infants Hb F binds O2 at lower tension than Hb A

Answer 23

Fetal Hb (Hb F) = 2 α and 2 γ subunits

Question 24

an abnormal Hb typical for sickle cell anemia

Answer 24

Hb S – in β-globin chain Glu is replaced by Val

Question 25

INHERITED AUTOSOMAL RECESSIVE BLOOD DIASEASES

genetic defect results in reduced rate of synthesis of α- or β-globin chain → it causes the formation of abnormal Hb molecules → anemia
• are prevalent in populations where malaria was endemic – Arab-Americans, people of Mediterranean origin and Asians
• genetic counseling and genetic testing is recommended for families that carry a thalassemia trait

Answer 25

THALASSEMIAS