Biochemistry Facts from Previous Papers

·         Remember PKU has no cataract. It can present with blue eyes, light skin with an eczematoid rash, and hyperactive deep tendon reflexes.

·         Also in tyrosinemia, cataracts are unusual.

·         Multiple carboxylase deficiency in its infantile or early form is an autosomal recessive disorder and presents with these features in addition to tachypnea or apnea. Failure to thrive and lethargy or coma may also develop with time. The rash helps to distinguish this from other organic acidemias.

·         Ornithine transcarbamylase (OTC) deficiency is an X-linked disorder and is most severe in males. Superficially it looks like Reye syndrome, and in older children, OTC deficiency may mimic Reye syndrome.

·         Long-chain acyl-CoA deficiency (LCAD) is more severe than MCAD, which does not have associated skeletal or cardiac muscle involvement. Short-chain acyl-CoA deficiency (SCAD) does not manifest hypoketotic hypoglycemia.

·         Fabry’s disease has no Mental retardation.

·         AIP is rare before puberty.

·         Biotinidase levels may reflect enzymatic deficiencies affecting carbohydrate and amino acid (organic acid) metabolism. Both enzymatic pathways require biotinidase.

·         In rhizomelic chondrodysplasia punctata, plasma levels of phytanic acid and erythrocyte plasmalogens are elevated.

·         PATHWAYS AND THE ORGANELLES IN WHICH THEY TAKE PLACE :

GLYCOLYSIS --------------------- CYTOPLASM

T.C.A CYCLE --------------------- MITOCHONDRIA

FATTY ACID SYNTHESIS ---- CYTOPLASM

FATTY ACID OXIDATION ---- MITOCHONDRIA

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KETONE BODY SYNTHESIS - MITOCHONDRIA

KETONE BODY OXIDATION – MITOCHONDRIA

H.M.P SHUNT --------------------- CYTOPLASM

GLUCONEOGENESIS ----------- CYTOPLASM AND MITOCHONDRIA

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FATTY ACID ELONGATION – S . E . R

VERY LONG CHAIN FATTY ACID OXIDATION – PEROXISOME

ETHER PHOSPHOLIPID SYNTHESIS – PEROXISOME

CHOLESTEROL SYNTHESIS – CYTOPLASM AND ENDOPLASMIC RETICULUM .

·         List of enzymes which use zinc as a cofactor are :

1. glutamate dehydrogenase

2. alcohol dehydrogenase

3. lactate dehydrogenase

4. carbonic anhydrase

5. alkaline phosphatase

6. DNA polymerase

7. RNA polymerase

8. delta-ALA dehydratase

9. superoxide dismutase

10. pancreatic carboxypeptidase

·         New Hb & Effect:

Hb Bristol-No functional Change

Hb Sydney- No functional Change

Hb Hikari- Acceptable Mistake

Hb S- Partially Acceptable Mistake

Hb M- Unacceptable Mutations

Hb Tak- Nonsense Mutations

Hb Constant Spring- Production of “Run on Polypeptide”

Cupric Cytochrome oxidase Ferrous or Ferric Catalase

Cytochrome (via Heme)

Nitrogenase

Hydrogenase Magnesium Glucose 6-phosphatase

Hexokinase Manganese Arginase Molybdenum Nitrate reductase Nickel Urease Selenium Glutathione peroxidase Zinc Alcohol dehydrogenase

Carbonic anhydrase

DNA polymerase