Lactoferrin activates plasma membrane oxidase and Na+/H+ antiport activity.
Lactoferrin is a growth stimulant. The basis for this effect is not clear since it is not thought to be involved in iron uptake through endocytosis. Ferric lactoferrin supports external ferrous chelate formation by K562 and HeLa cells, and ferric lactoferrin stimulates the reduction of external ferric iron by cells. Ferric lactoferrin also stimulates NADH oxidase activity in isolated rat liver plasma membranes and stimulates amiloride sensitive proton release from K562 cells. The evidence that ferric lactoferrin can participate in oxidoreduction reactions at the plasma membrane leading to activation of Na+/H+ exchange provides an alternative explanation for the proliferative effect.
Sun
I L
IL
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907.
Crane
F L
FL
Morré
D J
DJ
Löw
H
H
Faulk
W P
WP
D000584:Amiloride / Q000494:pharmacology; D000906:Antibodies; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004789:Enzyme Activation; D006133:Growth Substances; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007781:Lactoferrin / Q000276:immunology / Q000494:pharmacology*; D009097:Multienzyme Complexes / Q000378:metabolism*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D017923:Sodium-Hydrogen Exchangers; D014168:Transferrin / Q000494:pharmacology
D000906:Antibodies; D002352:Carrier Proteins; D006133:Growth Substances; D009097:Multienzyme Complexes; D017923:Sodium-Hydrogen Exchangers; D014168:Transferrin; D000584:Amiloride; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases; D007781:Lactoferrin