39. Pentose Phosphate Pathway Flashcards

1
Q

pentose phosphate pathway also known as

A

texose monophosphate shunt

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2
Q

what is pentose phosphate pathway used for

A
  1. produces NADPH
  2. produces ribose -5- phosphate-> nucleotides
  3. provides mechanism for use of 5-carbon sugars
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3
Q

what is the substrate of pentose phosphate pathway

A

glucose -6- phosphate

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4
Q

where does pentose phosphate pathway happen

A
  • RBC
  • liver
  • adipose
  • adrenals
  • thyroid
  • testes
  • lactating mammaries

•cytosol

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5
Q

important products of pentose phosphate pathway

A

NADPH

ribose-5-phosphate

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6
Q

rate limiting step of pentose phosphate pathway

A

Glucose-6-phosphate -> 6-phosphogluconate

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7
Q

oxidative, irreversible phase of PPP

A

first phase

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8
Q

non-oxidative , reversible phase of PPP

A

second phase

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9
Q

key enzymes of PPP

A

first phase: glucose-6- phosphate dehydrogenas

second: transketolases
cofactor: thiamine

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10
Q

product of first phase of PPP

A

2 NADPH

ribulose-5-phosphate

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11
Q

product of second phase of PPP

A

ribose-5-phosphate
fructose-6-phosphate
glyceraldehyde-3-phosphate
other carbs

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12
Q
  • used for reductive biosynthesis of FA and steroids
  • gluthathione reduction inside TBCs
  • synthesis of Nitric oxidfe
  • oxyge dependent bactericidal mechanisms of WBCs
A

NADPH

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13
Q

gluthathione (G-SH) removes H2O2 in a reaction catalyzed by

A

gluthathione peroxidase

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14
Q

reduced gluthathione is generated by

A

gluthathione reductase

requires NADPH

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15
Q

most common disease producing enzyme abnormality in humans

A

glucose-6- phosphate dehydrogenase deficiency

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16
Q

pathology of G6PD deficiency

A
  • dec NADPH in RBCs
  • dec activity of gluthathione reductase
  • free radicals and peroxides accumulate

oxidative stress -> hemolytic anemia

17
Q

precipitating factors of G6PD deficiency

A
  1. infection – most common
  2. drugs (sulfonamides, primaquine, choramphenicol)
  3. fava beans
18
Q

altered Hgb that precipitates within RBCs

A

•Heinz bodies

19
Q

abnormally shaped RBCs due to phagocytic removal fo heinz bodies in spleen

A

Bite cells

20
Q

deficiency in NADPH oxidase

•results in severe, persistent, chronic pyogenic infections caused by catalase-positive bacteria

A

Chronic granulomatous disease

21
Q

this converts molecule oxygen into superoxide in leukocytes (neutrophils, macrophages)
and used in the respiratory burst that kills bacteria

A

NADPH oxidase