Galactose metabolism
- 1. GALACTOSE METABOLISM • DR ROHINI C SANE • PROFESSOR • DEPARTMENT OF BIOCHEMISTRY • DR D Y PATIL MEDICAL COLLEGE • EBENE
- 2. GALCTOSEMIA • INBORN ERROR OF METABOLISM • BABIES WITH DEFECT CANNOT UTILISE GALACTOSE • GALACTOSE FROM MILK –PART OF MILK –ONLY FOOD OF BABIES • NORMAL CONDITION –GALACTOSE CONCENTRATION IN SYSTEMIC BLOOD –NIL • GALACTOSEMIA –HIGH LEVEL OF GALACTOSE IN BLOOD
- 3. SOURCES OF GALACTOSE • INTESTINAL HYDROLYSIS OF DIETARY LACTOSE PRESENT IN MILK • IMPORTANCE OF GALACTOSE –ESSENTIAL FOR FORMATION OF CERTAIN GLYCOPROTEINS,CERBROSIDES ,MILK DURING LACTATION LACTOSE +LACTASE GLUCOOSE +GALACTOSE ABSORPTION OF LACTOSE - ACTIVE TRANSPORT IN INTESTINAL LUMINAL CELLS LACTOSE -CARRIED BY PORTAL BLOOD TO LIVER PORTAL BLOOD THAT ENTERS LIVER CONTAINS GLUCOSE +GALACTOSE +FRUCTOSE SYSTEMIC BLOOD THAT LEAVES LIVER CONTAINS GLUCOSE + FRUCTOSE
- 4. METABOLISM OF GALACTOSE(LIVER) GALCTOSE GLYCOGEN ATP ADP GALACTOKINASE (1) GALCTOSE 1 PHOSPHATE UDP GLUCOSE GALACTOSE 1 PHOSPHATE UDP GALACTOSE EPIMERASE (3) URIDYL TRANSFERASE (2) GLUCOSE 1 PHOSPHATE UDP GALACTOSE MUTASE LACTOSE SYNTHETASE GLUCOSE 6 PHOSPHATE GLYCOLYSIS LACTOSE
- 5. GALACTSEMIA THREE AUSOMAL RECESSIVE INBORN ERRORS OF GALACTOSE METABOLISM 1. GALACTOKINASE DEFICIENCY 2. GALACTOSE 1 PHOSPHATE URIDYL TRANSFERSE (GALT) 3. GALACTOSE 4 EPIMERASE DEFICIENCY
- 7. I GALACTOKINASE DEFICIENCY • GALACTOSE +ATP+ GALACTOKINASEGALACOSE 1 PHOSPHATE • CHARACTRISTICS • ACCUMULATION OF GALACTOSE IN BLOOD & TISSUES • CATARACT FORMATION DUE TO REDUCTION OF GLUCOSE BY ALDOSE REDUCTASE TO GALACTIOL( DULCITOL)---LENSE BECOMES IMPERABLE •
- 10. GALACTOSE 1 PHOSPHATE URIDYL TRANSFERSE (GALT) • INCIDENCE : 1 IN 50000 BIRTHS • ENZYME DEFICIENCY : GALACTOSE 1 PHOSPHATE URIDYL TRANSFERSE (GALT) • ACCUMULATION OF GALACTOSE & GALACTOSE -1-PHOSPHATE • CLINICAL AND BIOCHEMICAL FEATURES VOMITING & DIARRHOEA WITH FAILURE TO THRIVE HYPOGLYCEMIA JAUNDICE ,HEPATOMEGALY,CIRRHOSIS IRREVERSIBLE MENTAL RETARDATION RENAL TUBULAR DAMAGE &GENERALISED AMINOACIDURIA (FANCONI SYNDROME )DUE TO GALACTOSE- 1 -PHOSPHATE IN KIDNEY BACTERIAL SEPSIS WITH E .COLI LEADING TO DEATH
- 11. III GALACOSE- 4- EPIMERASE DEFICIENCY • VERY RARE AND ASYMPTOMATIC • ENZYME MAY BE FOUND DEFICIENT IN ERYTHROCYTES BUT FOUND IN LIVER
- 13. MANAGEMENT OF GALACTOSEMIA • ALL THREE TYPES OF GALACTOSEMIA CAN BE TREATED BY ELIMINATION OF GALACTOSE IN DIET (MILK & MILK PRODUCTS )
- 21. THANK YOU