HMP

Question 1

Other names

Answer 1

PPP
6- phophogluconate pathway

Question 2

Location

Answer 2

Cell : cytosol
Organ : in liver , mammary glands and adipose tissue which needs NADPH FOR FAT synthesis and testes , ovaries and placenta and adrenal cortex which needs NADPH FOR steroid hormones specifically

Question 3

Funtion

Answer 3

NADPH production
Ribose 5 phosphate production for necliotide synthesis

The function represents a link between carb , lipogensis and necliotide synthesis

Question 4

Phases

Answer 4

1- irreversible oxidative reactions
2- non reversible non oxidative reactions

Question 5

Steps

Answer 5

B glucose 6 phosphate
Rate limiting ~> G6PD- transketolase - transaldolase

H2o is used
Co2 is out
2 NADPH ARE PRODUCED

Some cells that carry out reductive biosynthesis reactions need NADPH more than ribose 5 phosphate so in this case transketolase and transaldolase converts ribulose 5 phosphate to glyceraldehyde 3 phosphate and glucose 6 phosphate which are intermediates for glycolysis

In contrast, some cells need ribose 5 phosphate for nucleotide synthesis more than NADPH so in this case the nonoxidative reactions can provide synthesis of ribose 5 phosphate from glyceraldehyde 3 phosphate and glucose 6 phosphate , in abscence of oxidative steps

Question 6

Function of NADPH

Answer 6

1- biosynthesis ( eg lipid )
2- maintenance of reduced glutathione in rbcs to protect it from reactive o2 species
3- bacteriocidal activaty in polymorphonuclear leukocyte through NADPH oxidase that produces H2O2 that kill bacteria

Question 7

How NADPH maint the reduced glutathione

Answer 7

O2 spontaneously can convert to H2O2 due oxidant stress eg drugs or fava beans or infections , and if it accumulates it causes hemolyisis and Hb denaturation to heinz bodies , glutathione peroxidase get rid of this structure by converting it to H2O and become oxidized , glutathione reductase by the help of NADPH as h2 source reduces the oxidized glutathione

Question 8

Talk about favism

Answer 8

1- G6PDD
2- X linked recessive disease
3- thus it is more common in men
4- symptoms: acute episodic ( common ) or chronic hemolysis ( rare)
5-Female heterogeneous for G6PDD is resistant to malaria
6-mechanism of hemolysis :
The o2 spontaneously can convert to h2o2 that can damage protein and lipid in cell
( Hb denaturation to heinz bodies ) and weakening the lipid membrane causing hemolysis , this process is accelerated by some drugs , fava beans and infections like pneumonia and infectious hepatitis