Abstract
We have previously characterized a brush-border membrane receptor that facilitates iron uptake from human lactoferrin. The receptor is specific for human and monkey lactoferrin and does not recognize human transferron or bovine lactoferrin. In this study, iron uptake from lactoferrin fragments was studied, as well as from lactoferrin partially saturated with iron. Brush-border membrane vesicles (BBMV) prepared from infant rhesus monkey small intestine efficiently accumulated iron from lactoferrin half-molecules, although competition experiments showed that intact lactoferrin has a higher affinity toward the receptor. Lactoferrin partially saturated with iron also effectively delivered iron to the receptor, whereas the affinity was lower than for lactoferrin saturated with iron. Lactoferrin also carries a large proportion of human milk manganese, and receptor-mediated uptake of lactoferrin-bound manganese into BBMV was demonstrated, although this complex had lower affinity than that found for iron-lactoferrin. Thus, although the receptor has a preference for intact iron-saturated lactoferrin, partially digested lactoferrin and partially iron-sulfated lactoferrin can also deliver iron to the receptor. Therefore, these molecular species, which are likely to occur in the gastrointestinal tract of the infant, may contribute to the high degree of iron absorption from human milk lactoferrin.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Gastrointestinal and Liver Physiology |
| Volume | 257 |
| Issue number | 6 |
| State | Published - 1989 |
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Keywords
- infants
- iron absorption
- lactoferrin receptor
ASJC Scopus subject areas
- Gastroenterology
- Physiology
Cite this
Fe-saturation and proteolysis of human lactoferrin : Effect on brush-border receptor-mediated uptake of Fe and Mn. / Davidson, L. A.; Lonnerdal, B.
In: American Journal of Physiology - Gastrointestinal and Liver Physiology, Vol. 257, No. 6, 1989.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Fe-saturation and proteolysis of human lactoferrin
T2 - Effect on brush-border receptor-mediated uptake of Fe and Mn
AU - Davidson, L. A.
AU - Lonnerdal, B.
PY - 1989
Y1 - 1989
N2 - We have previously characterized a brush-border membrane receptor that facilitates iron uptake from human lactoferrin. The receptor is specific for human and monkey lactoferrin and does not recognize human transferron or bovine lactoferrin. In this study, iron uptake from lactoferrin fragments was studied, as well as from lactoferrin partially saturated with iron. Brush-border membrane vesicles (BBMV) prepared from infant rhesus monkey small intestine efficiently accumulated iron from lactoferrin half-molecules, although competition experiments showed that intact lactoferrin has a higher affinity toward the receptor. Lactoferrin partially saturated with iron also effectively delivered iron to the receptor, whereas the affinity was lower than for lactoferrin saturated with iron. Lactoferrin also carries a large proportion of human milk manganese, and receptor-mediated uptake of lactoferrin-bound manganese into BBMV was demonstrated, although this complex had lower affinity than that found for iron-lactoferrin. Thus, although the receptor has a preference for intact iron-saturated lactoferrin, partially digested lactoferrin and partially iron-sulfated lactoferrin can also deliver iron to the receptor. Therefore, these molecular species, which are likely to occur in the gastrointestinal tract of the infant, may contribute to the high degree of iron absorption from human milk lactoferrin.
AB - We have previously characterized a brush-border membrane receptor that facilitates iron uptake from human lactoferrin. The receptor is specific for human and monkey lactoferrin and does not recognize human transferron or bovine lactoferrin. In this study, iron uptake from lactoferrin fragments was studied, as well as from lactoferrin partially saturated with iron. Brush-border membrane vesicles (BBMV) prepared from infant rhesus monkey small intestine efficiently accumulated iron from lactoferrin half-molecules, although competition experiments showed that intact lactoferrin has a higher affinity toward the receptor. Lactoferrin partially saturated with iron also effectively delivered iron to the receptor, whereas the affinity was lower than for lactoferrin saturated with iron. Lactoferrin also carries a large proportion of human milk manganese, and receptor-mediated uptake of lactoferrin-bound manganese into BBMV was demonstrated, although this complex had lower affinity than that found for iron-lactoferrin. Thus, although the receptor has a preference for intact iron-saturated lactoferrin, partially digested lactoferrin and partially iron-sulfated lactoferrin can also deliver iron to the receptor. Therefore, these molecular species, which are likely to occur in the gastrointestinal tract of the infant, may contribute to the high degree of iron absorption from human milk lactoferrin.
KW - infants
KW - iron absorption
KW - lactoferrin receptor
UR - http://www.scopus.com/inward/record.url?scp=0024803796&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0024803796&partnerID=8YFLogxK
M3 - Article
C2 - 2558579
AN - SCOPUS:0024803796
VL - 257
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 6
ER -