BIOC 3560 Lecture Notes - Lecture 3: Hexokinase, Glucokinase, Anabolism
6 Feb 2020
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E set the speed of the pathway depending on the activity of enzyme limited usually by substrate avaibility enzyme in excess exergonic and irreversible targets of metabolic regulation eachstep. In muscle hexokinase 1 is expressed normally has maximal activity if glucose6p increases enzyme is inhibited cvefeedback. Phosphofructokinase i allostery when fructosegp a glucokinase regulatory protein hides hexokinaseiv in the nucleus t glucose weakens the enzymeregulator interaction which encourages cytosolic localization. Phosphorylation by pfk1 commits fructose6pcinequilibrium withagp to glycolysis. Aatp binds to an allosteric site on pkf l and lowers affinity for fgp. Citrate increases inhibition byatp fructose2,6 biphosphate is a strong activator. When atpiv rer fgp affinity allowspfki to be more active. Pktransfers p from phosphoenolpyruvate to adp this yields pyruvate t molecule of atp. High atdallosterically inhibits pk which i affinity for pep. Acetyl coaandlong chain tatty acids also inhibit pk important fuel for citricacid cycle when plentiful so is atp.
