KINE 2P97 Lecture Notes - Lecture 4: Nicotinamide Adenine Dinucleotide, Enzyme Inhibitor, Inosine
8 May 2018
School
Department
Course
Professor
KINE 2P97
Muscle Physiology & Exercise Metabolism
Control of Glycolysis
- hexokinase (HK)
- glycogen Phosphorylase (Phos)
- phosphofructokinase (PFK)
- there are regulated enzymes that combine to control flux through glycolysis
- everything else controlled by mass action
Hexokinase (HK)
- hexokinase inhibited by increase of glucose-6 phosphate
o end product inhibition
o high glycogen breakdown (or glucose uptake) cause increase G6P and decrease
HK activity
o ultimately decreased glucose uptake
Glycogen Phosphorylase (Phos)
- covalent and allosteric control
- of these – the allosteric regulation is most important in skeletal muscle
Regulatory Control of Glycolysis
- regulatory controls are logical
- the bi-products of ATP hydrolysis (ADP/AMP/IMP) turn on glycolysis and more energy is
produced
- energy containing molecules and products turn off glycolysis to slow or stop energy
production
- egative feedak or feedak ihiitio
- availability of coenzyme NAD+ is critical for glycolytic flux
Muscles contract ATP broken down and ADP + Pi increases ADP converted to AMP by
Myokinase(AK) ADP, AMP, Pi activate glycogen phos. and PK Glycolysis increases and
more ATP is produced
Covalent and Allosteric Regulation
Covalent
- phosphorylation/dephosphorylation cycle
- active and inactive enzyme form
Allosteric
- allosteri ativator positive effetor
- allosteri ihiitors egative effetors
Role of Inosine Monophosphate (IMP)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Everything else controlled by mass action there are regulated enzymes that combine to control flux through glycolysis. Hexokinase inhibited by increase of glucose-6 phosphate: end product inhibition, high glycogen breakdown (or glucose uptake) cause increase g6p and decrease. Of these the allosteric regulation is most important in skeletal muscle. Regulatory control of glycolysis regulatory controls are logical the bi-products of atp hydrolysis (adp/amp/imp) turn on glycolysis and more energy is produced. Energy containing molecules and products turn off glycolysis to slow or stop energy production (cid:858)(cid:374)egative feed(cid:271)a(cid:272)k or (cid:858)feed(cid:271)a(cid:272)k i(cid:374)hi(cid:271)itio(cid:374)(cid:859) Availability of coenzyme nad+ is critical for glycolytic flux. Muscles contract atp broken down and adp + pi increases adp converted to amp by. Myokinase(ak) adp, amp, pi activate glycogen phos. and pk glycolysis increases and more atp is produced. Amp imp + ammonia: catalyzed by amp deaminase. Activating phosphokinase is a covalent regulator of phosphorylase. Feedforward signal: enhances glycogen breakdown when really needed.
