pentose phosphate pathways & sugar metabolism

the pentose phosphate pathway makes [ ] and [ ]

NADPH and ribose-5-phosphate

there are two phases of the pentose phosphate pathway [ ] and [ ]

oxidative phase and non-oxidative phase

the first step of the oxidative phase uses the enzyme [ ] and creates [ ]

glucose-6-P dehydrogenase

6-P-gluconolactone

creates the first NADP

the second step of the oxidative phase uses the enzyme [ ] and creates [ ]

lactonase

6-P-gluconate

the third step of the oxidative phase uses the enzyme [ ] and creates [ ]

6-P-gluconate dehydrogenase

ribulose-5-P, CO2, NADPH

rate-limiting step

the non-oxidative phases of the PPP uses the enzymes [ ] and [ ]

transketolase and transaldolase

the non-oxidative phases of the PPP produce ?

2 Fructose-6-P

1 Glyceraldehyde-3-P

a deficiency of [ ] leads to low levels of NADPH and the body cannot reduce glutathione leading to oxidative stress and hemolysis

glucose-6-phosphate dehydrogenase

PPP occurs in ?

liver, adipose, mammary gland - fatty acids synthesis

testes, ovaries, adrenal - steroid synthesis

RBCs - glutathione reduction

fructose is metabolized mainly in the [ ]

liver

the enzymes involved in fructose metabolism include [ ], [ ], [ ]

fructokinase

aldolase B

triose kinase

intermediates formed from fructose metabolism enter [ ] at a [ ]

glycolysis at a triose level

fructose metabolism is NOT [ ] regulated

insulin

Aldolase B deficiency can lead to [ ]

fructose-1-P trapped » ATP depletion » liver damage

galactose metabolism occurs from [ ]

lactose digestion

the enzymes formed from glucose metabolism include [ ],[ ], and [ ]

galactokinase

galactose-1-P uridyltransferase

epimerase

Uritidyltransferase deficiency can lead to [ ]

Gal-1-P buildup » liver damage, CNS, cataracts

in diabetic cells, excess glucose is converted in [ ] via aldolase reductase

sorbitol

sorbitol dehydrogenase cannot keep up with sorbitol production in diabetic cells leading to [ ]

osmotic stress » lense damage - cataracts

the PPP pathway is regulated by the [ ]:[ ] ratio, and insulin increases mRNA for NADPH-linked enzymes

NADPH:NADP+

the galactose pathway is regulated from [ ] deficiencies

enzyme

mnemonic for PPP

Good Luck Passing Today

G6PD » Lactonase » Phosphogluconate dehydrogenase » Transketolase

mnemonic for fructose pathway

Freaky Fruits Are Toxic

Fructose » Fructokinase » Aldolase B » Triose kinase

mnemonic for galactose pathway

Girls Get Ugly Easily

Galactose » Galactokinase » Uritdyytansferase » Epimerase