Normal & Abnormal Hemoglobin derivatives

Dr. Rohini C Sane

NORMAL HAEMOGLOBIN DERIVATIVES

HAEMOGLOBIN DERIVATIVES

COLOR CONCENTRATION

Oxy –Hb Red 97%

Deoxy –Hb purple Cyanosis > 5%

CO –Hb Cherry red 0.16%

Sulph –Hb Green High in cockroaches

Hemoglobin derivatives

1.Meth Hb ( synthesis in living system by H₂O₂, drugs ,free radicals

2. Carboxy Hb

Meth Hemoglobin –Meth- Hb

• Concentration of serum Meth- Hb= ( < 1% )

• Brown color of dried blood ( Meth –Hb ) & meat ( meth- myoglobin )

Normal Hemoglobin Meth- Hb

synthesis by oxygenation synthesis by oxidation ( BY H2O2 ,free radicals ,drugs )

O ₂ loosely binds Fails to bind to O ₂ ( H₂O molecule occupies O ₂ site in Heme )

Fe ²⁺ state ( Ferrous ) –no oxidation of Fe ²⁺ ( ferrous ) to ferric ( Fe³⁺ )

Fe ²⁺ Fe³⁺

Fe ²⁺

Fe ³⁺

Meth –Hb reductase

75 %

NADH DEPENDENT

20 %

NADPH DEPENDENT

5%GLUTATHIONE DEPENDENT

Concentration of serum Meth Hb > 1%

(normal < 1% )

Decrease capacity for oxygen binding therefore transport

Increase concentration of Meth –Hb (Cyanosis )

Meth Hemoglobinaemia ( acquired or congenital)

Congenital Meth Hemoglobinaemia

• Hemoglobin M ( proximal or distal Histidine of α or β globin chain replaced by Tyrosine

• Deficiency of cytochrome b5 reductase

• 10-15% Hb as Meth –Hb ( normal < 1% )

Histidine -----------------------------Histidine

•58 distal 87 proximal

Histidine ------------------------------Histidine

•63 distal 92 proximal

α Globin chain

β Globin chain

Mutation in hemoglobin- Histidine to Tyr ( formation of Meth-Hb )

Acquired or Toxic Meth Hemoglobinaemia

1. Drinking of water contain Aniline dyes or nitrates

2. Drugs –Acetaminophen, Phenacein, Sulphanilamide ,Amyl nitrite , Na- nitroprusside

3. Person with G-6 –PD deficiency

NADPH synthesis

↓

Decrease dependent Meth–Hb reductase (Normal-75%)

Deficient HMP

Person with G-6 –PD deficiency

MANIFESTATION OF DISEASE EASILY

TREATMENT – SMALL DOSES OF REDUCING AGENTS

DECREASE IN METH-Hb Hb ( inadequate )

5% NADPH dependent Meth Hb reductase

Meth –Hemoglobinaemia

Treatment of Acquired Meth –Hemoglobinaemia

2mg/ body Kg weight intravenous leucomethylene blue substitute for NADPH

Preparation of Meth –Hb in laboratory

5 drops of blood + sodium Ferri-cyanide (oxidizing agent ) formation of Meth hemoglobin (brown )-dark band at 633 nm (red region )

Preparation of Reduced –Hb in laboratory

5 drops of blood + Sodium dithionite reduced Hb ( purple ) reversible reaction ( reversed by atmospheric oxygen )

Meth Hemoglobinemia

• ( a ) Ascorbic acid

• (200- 500 mg/day)

• (b ) Methylene blue

• -200-500 mg/day

• Gene therapy

Treatment of Meth Hemoglobinaemia

Decrease level of Meth –Hb to 5-10% (cyanosis reversed)

Carboxy –Hb (CO-Hb )Carbon monoxide ( CO )

1. produced by incomplete combustion –occupational hazard

2. Colorless

3. Odorless

4. Tasteless

5. Toxic industrial pollutant

6. Affinity of CO for Hemoglobin is 200 more than that for Oxygen( O₂ )

7. NORMAL INDIVIDUAL SMOKER

CONCENTRATION OF CO –Hb < 0.16 gm % > 4 gm%

One cigarette 10-20 ml of CO in Lungs

Heme of hemoglobin

Heme of myoglobin

Heme of cytochrome

CO

Clinical manifestation of increased CO

1. Conc of CO-Hb > 20 gm%

2.Head ache

3. Nausea

4.Vommitting

5. Breathlessness

6. Irritability

7. 40-60 % saturation of Hb with CO DEATH

8.

Identification of CO-Hb by absorption spectroscopy

• Band pattern for normal Hb & CO –Hb similar ( band 580 & 540nm )

Normal Hb

Reduced Hb

Oxy – Hb Deoxy Hb

Entry of O₂ Oxy – Hb reformed (reversible )

Carboxy Hb

Fails to form Reduced Hb

Carboxy Hb (CO high affinity for Hb )

Na- Dithionite

vigorous shaking