Biochemistry Ch 15,16,17

Front 1

What is GLUT1?

Back 1

-glucose transporter
-all mamalian species
-basal glucose uptake

Front 2

What is GLUT2?

Back 2

-Liver and pancreatic beta-cells
-in pancreas plays role in insulin regulation
-in liver removes excess glucose from blood

Front 3

GLUT3

Back 3

-all mammalian species
-basal glucose uptake

Front 4

GLUT4

Back 4

-muscle and fat cells
-amount in muscle plasma membrane

Front 5

GLUT5

Back 5

-small intestine
-increases with endurance training
-primarily a fructose transporter

Front 6

Stage one of Glycolysis

Back 6

-glucose-> fructose-1,6-bisphosphate
-phosphorylation, isomerization, phosphorylation

Front 7

Stage two of Glycolysis

Back 7

aldolase
F-1,6-BP --> DHAP + GA-3-P
triose phosphate isomerase
DHAP--> GA-3-P

Front 8

Stage 3 of Glycolysis

Back 8

GA-3-P<-->1,3-bisphosphoglycerate
1,3-BPG<--> 3-PG +ATP
3-PG<--> 2-PG
2-PG<--> PEP
PEP---> pyruvate + ATP

Front 9

NET RXN glucose--> pyruvate

Back 9

Glucose + 2 Pi + 2 ADP + 2 NAD+ ------->
2 pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H2O
NET 2 ATP

Front 10

NADH in glycolysis-areobic

Back 10

Under areobic conditions, the NADH generated during glycolysis is used to fuel mitochondrial ATP synthesis via oxidative phosphorylation producing either 2 or 3 equivalents of ATP depending on whether the glycerol phosphate or the malate-aspartate shuttle is used to transport the electrons from cytoplasmic NADH into the mitochondria. This cycle creates a continuous pool of cytoplasmic NAD+ essential for glycolysis to continue.

Front 11

NADH in glycolysis-aneorobic

Back 11

pyruvate is converted to lactate by lactate dehydrogenase:
Pyruvate + NADH + H+-->Lactate + NAD+
This reduction is essential to form NAD+ for the glceraldehyde-3-phosphate dehydrogenase reaction, without which glycolysis will stop.

Front 12

Phosphofructokinase 1

Back 12

PFK 1 is a tetramer of
-4 identical subunits. Each subunit consists of,two separate domains, catalytic and allosteric.

Front 13

Phosphofructokinase 1

Back 13

Regulation of muscle and liver PFK 1.
Muscle enzyme – Inhibitors; high levels of ATP and
low pH.
Activator, AMP.

Front 14

Phosphofructokinase 1

Back 14

Liver enzyme – Inhibitors; high levels of ATP and citrate (citrate enhances the inhibitory
effect of ATP)
Activator, F-2,6 BP (binding of F-2,6 BP increases the affinity of PFK 1 for F-6-PO4 and
decreases the inhibitory effect of ATP)

Front 15

Phosphofructokinase 2

Back 15

Fructose-2-6-BP is an important regulator of glycolysis because it is an allosteric activator of PFK I. It is synthesized from F-6-P and ATP by the action of phosphofructokinase 2 (PFK 2). PFK 2 is a bifunctional enzyme, housing both the kinase and phosphatase (FBPase 2) activities on a single polypeptide chain. FBPase 2 hydrolyzes F-2,6-BP to form F-6-P and Pi.