Biochemical Reactions and Enzyme Kinetics - Introduction to Biomedical Engineering - page 490

The eighth step involves the reaction of 3-phosphoglycerate with the enzyme phospho-
glycerate mutase to create 2-phosphoglycerate and is given by

ð 8 : 96 Þ

The ninth step involves the reaction of 2-phosphoglycerate with the enzyme enolase to
create phosphoenolpyruvate and water, and is given by

ð 8 : 97 Þ

H þ with the The last step involves the reaction of phosphoenolpyruvate, ADP, and

enzyme pyruvate kinase to create pyruvate and ATP and is given by

B 10

PP þ PK ! PPPK

K 10

PPPK þ ADP ! PV þ ATP þ PK

ð 8 : 98 Þ

q PP ¼ K

q P 2 GEN K 9 q PP q EN q H 2 O B q PP q PK

9 10

q PPPK ¼ B q PP q PK K q PPPK q ADP

10 10

q PV ¼ K q PPPK q ADP

10

The equations for ATP and ADP in the cytosol are

q ATP ¼ K q ATP q GHx K q F 6 PPF q ATP þ K q BPPGK q ADP þ K q PPPK q ADP þ J ATP

1 3 7 10

ð 8 : 99 Þ

q ADP ¼ K q ATP q GHx þ K q F 6 PPF q ATP K q BPPGK q ADP K q PPPK q ADP þ J ADP

1 3 7 10

where are the net usage of ATP and ADP from other processes, such as the

reactions in Sections 8.5.2 and 8.5.3 in the mitochondria and the Na-K pump described in
Section 8.4.4.

J ATP and J ADP

ADP and ATP Movement in/out of the Mitochondria
Let's assume that the movement of ADP and ATP through the mitochondria's mem-
branes is by diffusion from the cytosol through the outer membrane and carrier-mediated
diffusion through the inner membrane. Further, we assume that ADP only enters the mito-
chondria and that ATP only leaves the mitochondria for simplicity. The equations that
describe this transport are given in Eqs. (8.100) and (8.101).