Compounds of High Phosphoryl Transfer Potential Flashcards
Chemical Transformations
Cleavage:
Condensation:
Cleavage
Condensation
Delta G Phosphoenolpyruvate
61.9 kjmol
Delta G ADP
Bioenergetic Metabolic Systems
Oxidative Phosphorylation
High Energy phosphate transfer (phosphagen)
Glycolysis
Oxidative Phosphorylation
Lots of ATP- Slow
Actomyosin ATPase - Crossbridge cycling
60-70%
Phosphagen
Little ATP- Fast
SR ATPase - Calcium Cycling
20-30%
Glycolysis
More Complex-lots of ATP
Sarcolemma ATPase - Na+/K= (sodium potassium pump) cycling
<10%
What does A. Represent?
Second Messenger System
Cyclic AMP
Stable
Causes cascade of processes
Delta G^; for ATP
-30.5 kJ/mol (-7.3 kcal/mol)
Large and negative
favorable
ATPs role in most enzyme reactions
phosphoryl donor
Delta Gp
Phosphorylation potential
Steps of ATP Group Transfer
- Phosphoryl group or adenylate moiety (AMP) transferred to substrate or amino acid residue on enzyme
- phosphate containing moiety is displaced generating Pi or AMP
Exception to ATP group transfer
Muscle contration: provide protein confirmation
ATP processes stimulated by exercise
- Cross Bridge Cycling (muscle contraction)
- Ion Transport
- Signal amplification
ATP content of skeletul muscle during rest
~6mmol/kg
Exercise effect on substrate levels in muscle
ATP decreases
ADP and Pi Increase
Adenylate Kinase Reaction
(myokinase) 2 ADP <> AMP+ATP
Does not use PCr
Creatine Structure
Same as an AA but not one that makes up proteins
Creatine Phosphate Structure
Creatine with a phosphoryl group attached to one of the nitrogens
PCr Pathway benefit
Fastest Source of ATP resynthesis
When is PCr most valuable
maximal exercise
Number of reactions to generate ATP from ADP with PCr
one
PCr+ADP+H+ <> ATP+Cr
CP phosphoryl transfer potential vs ATP
PCr:-10.3 kcal/mol, bigger more negative
ATP: -3
CK Reaction
Creatine Kinase:
PCr+ADP+H+ <CK> ATP + Cr
Delta G^' = -3kcal/mol</CK>
Anaerobic alactic system
PCr system
does not need O2
does not generate lactate
PCr system during exercise
PCr depleated
ATP maintained
Cr increases
Genes for CK in mammals
2 cytosolic (brain and muscle)
2 mitochondrial
Cytosolic CK genes
CK-BB(CK1) Brain
CK- MB (CK2) heart
CK-MM (CK3) skeletal muscle
Mitochondrial CK genes
Involved in facilitation of oxidative phosphorylation
PCr affect on ADP
Phosphorylation (quick)
Phosphocreatine system during rest
CK reaction dominates
Phosphate transfer to Cr from ATP (oxidative phosphorylation) regenerates PC4
-this consumes ATP
-derived from aerobic metabolism
-EPOC