Glycolysis

Front 1

Hexokinase

Back 1

Trapping enzyme, phosphorylates glucose to G6P to keep it in the cell.
*increase free energy of glucose

This step requires an input of energy (ATP, where the phosphate comes from)

Front 2

Phosphoglucose isomerase

Back 2

Aldose to ketose; makes a symmetrical molecule (in its open chain form)

converts G6P to F6P

Front 3

Phosphofructokinase

Back 3

PFK, regulatory enzyme- once glucose reaches this point it is committed to catabolism

Produces F16bisphosphate to 2 interconvertible 3c sugars- DHAP and GAP

Front 4

Triose phosphate isomerase

Back 4

Catalyzes the reversible conversion of DHAP to GAP

Front 5

G3P dehydrogenase

Back 5

redox reaction, saves energy as it produces NADH

Adds phosphate to GAP to yield 1,3bisphosphoglycerate

Front 6

Phosphoglycerate kinase

Back 6

substrate level phosphorylation (produces ATP)

uses no ATP synthase or photosynthesis to make ATP from ADP

converts 13Bisphosphoglycerate to 3phosphoglycerate

Front 7

Phosphoglycerate mutase

Back 7

creates higher energy 2 phosphoglycerate; isomerization

Front 8

Enolase

Back 8

A dehydration reaction, water is released

2phosphoglycerate to phosphoenolpyruvate

Front 9

Pyruvate kinase

Back 9

Also substrate level phosphorylation

Front 10

Glycolysis yield

Back 10

2 pyruvate

uses 2 ATP (hexo and PFK)
makes 2 ATP (PGK and PK)
makes 2 NADH (G3PDH)

Front 11

Summary of how G3PDH works

Back 11

converts GAP to 1,3bisphosphoglycerate

1. ald of G3P reacts w/ sulfhydryl group of cysteine, hist (B:) withdraws e- to facilitate formation
2. transfer of hydride ion to NAD+ yields NADH and thioester int
3. NADH leaves and is replaced w/ NAD+ again
4. Pi attacks the thioester to form 1,3bisphosphoglycerate

Front 12

Fructose-1-phosphate pathway

Back 12

Liver

Fructose is phosphorylated by fructokinase (not PFK), resulting F1P is cleaved to GAP by fructose-1-phosphate aldolase

Front 13

Galactose-Glucose interconversion pathway

Back 13

Galactose + ATP produces galactose 1 phosphate; Galactose1phosphate + UDP-glucose --> UDP galactose + glucose 1 phosphate

UDPgalactose interconvertible w/ UDPglucose

Front 14

Regulation of Glycolysis occurs:

Back 14

w/ hexokinase
PFK
PK

Front 15

PFK

Back 15

tetramer w/ allosteric binding, ATP reduces activity while AMP increases activity

Front 16

pyruvate kinase

Back 16

also inhibited by ATP/AMP ratio (low is better, increases activity)

ALANINE (transam prod of pyruvate) is an allosteric inhibitor

last step of glycolysis; phosphorylation decreases activity

Front 17

PFK

Back 17

inhibited by citrate (first product of TCA)

activated by F26bisphosphate in LIVER

Front 18

F26bisphosphate

Back 18

synthesized from F6P; becomes more abundant as F6P increases

increases glycolysis when glucose is present

Front 19

Gluconeogenesis

Back 19

uses different enzymes:

PK--> Pyruvate carboxylase and PEP carboxykinase
PFK--> F16BPase
Glucokinase--> G6phosphatase

Front 20

Pyruvate to PEP

Back 20

1. (mito) Pyruvate to oxaloacetate (catalyzed by pyruvate carboxylase)
2. (cyto) Oxaloacetate to PEP (catalyzed by PEP carboxykinase)

Front 21

F16bisphosphate to F6phosphate

Back 21

committed step of gluconeogenesis; catalyzed by fructose16bisphosphatase; releases Pi