Biochemistry- Glucose transporters

Biochemistry
gLUCOSE TRANSPORTERS
sODIUM DEPENDENT AND independent transporters
GluT-1,2,3,4,5
Insulin-dependent GluT-4

1. GLUCOSE
TRANSPORTERS

2. INTRODUCTION
Glucose transporters are integral membrane glycoprotiens with molecular masses of about 50,000 Daltons, and each has 12 membrane-spanning alpha-helical domains.
Transporter exposes a single substrate binding site toward either the outside or the inside of the cell.
Binding of glucose to one site provokes a conformational change associated with tranpory, and releases glucose to the other side of the membrane.

3. GLUCOSE TRANSPORT
Glucose is an important fuel for contracting muscle, and normal glucose metabolism is vital for health.
Glucose enters muscle cell via facilitated diffusion through the GLUT4 glucose.
The glucose transport family comprises five members, named GLUT-1 to GLUT 5.
Secondary active transport is the mechanism of sodium glucose cotransport across the membranous barrier against concentration gradient of glucose.

5. GLUT-4
It is abundant in skeletal muscle and adipose tissue.
Insulin increases the number and activity of GLUT-4, thereby promoting entry of glucose in those tissues.
NOTE: Insulin is not required for glucose uptake by some tissues such as liver, brain and red blood cells.

8. SODIUM DEPENDENT GLUCOSE TRANPORT-1
•SGluT-1 Absorption from intestinal lumen into
intestinal cell is by co-transport mechanism
(secondary active transport).
•A membrane bound carrier protein is involved,
which carries glucose, along with sodium.
•This sodium is later expelled by sodium pump
with utilization of energy. So energy is needed
indirectly.
•The transporter in intestine is named by SGluT-1.
•Involved in glucose-galactose malabsorption.

9. SODIUM DEPENDENT
GLUCOSE TRANSPORT-2
•Transporter in kidney is called
SGluT-2.
•The SGluT-2 is defective in
congenital renal glycosuria.

10. THANK YOU