RBC and cancer metabolism Flashcards
what will be observed in the serum following intravascular hemolysis?
hemoglobinuria
what will be observed in the serum following extravascular hemolysis (spleen)?
bilirubin (jaundice) - Hb has already been dealt with by macrophages
what is accomplished by RBC metabolism?
- keeping iron reduced (2+)
- maintaining K/Ca gradients
- keeping protein SH groups reduced
- maintaining cell shape
what is the relationship between NADH and MetHb?
NADH transfers electrons to MetHb to replenish the 2+ state
what is the role of ATP in maintenance of K/Ca gradients?
maintenance of ions across membrane
how do RBCs keep protein thiol groups reduced?
transfer electrons from glutathione to thiol groups to keep them reduced
where does glutathione get the electrons for reduction of thiol groups?
NADPH
what is the result of RBC metabolism failure?
- cells fill with Ca2+
- cells release K+
- lose biconcave shape
what is the substrate that RBCs use for the PPP?
glucose-6-P
the RBC energy clutch bypasses which step of RBC metabolism?
phosphglycerokinase step converting 1,3-BPG to 3-phosphoglycerate
what is the result / purpose of the RBC energy clutch?
- no consumption of ADP
- net gain of ATP is zero
(saves one ADP expenditure and one ATP production per cycle)
in what circumstances is the energy clutch useful for RBC metabolism?
if cell is full of ATP but there is no ADP and you still need to make NADH
what regulates the energy clutch?
pH - lower pH increases activity - more NADH production
what are the two enzymes that compete for 1,3-BPG?
- phosphoglycerate kinase
2. diphosphoglyceromutase
what are the regulated steps of glycolysis in RBCs?
- hexokinase (glucose to glucose-6-P)
2. PFK1 (fructose-6-P to fructose-1,6-BP)
