Biomaterial Database

Zinc and copper binding proteins in human milk. 1982

B Lönnerdal, and B Hoffman, and L S Hurley

The proteins binding zinc and copper in human milk have been fractionated and identified, and the distribution of these trace elements among the different binding compounds has been determined. Casein was separated by ultracentrifugation and was found to contain 14% (range 5 to 21%) of the total zinc content in the milk and 28% (range 7 to 48%) of the total copper. Another zinc- and copper-binding protein was isolated by gel filtration and ion-exchange chromatography and identified as serum albumin by gel electrophoresis. Serum albumin in breast milk binds 28% of total zinc and 39% of total copper. The remainder of Zn and Cu was found to be in a low molecular weight form (29% (range 24 to 36%) of Zn; 24% (range 15 to 47%) of Cu) or associated to the fat (29% (range 20 to 45%) of Zn; 9% (range 1 to 21% of Cu). It is hypothesized that association constants of the different binding compounds as well as their concentrations will determine the relative distribution of zinc and copper among them and may affect bioavailability of these elements for the infant.

UI	MeSH Term	Description	Entries
D008895	Milk, Human	Milk that is produced by HUMAN MAMMARY GLANDS.	Breast Milk,Human Milk,Milk, Breast
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D001942	Breast Feeding	The nursing of an infant at the breast.	Breast Fed,Breastfed,Milk Sharing,Wet Nursing,Breast Feeding, Exclusive,Breastfeeding,Breastfeeding, Exclusive,Exclusive Breast Feeding,Exclusive Breastfeeding,Sharing, Milk
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier
D002364	Caseins	A mixture of related phosphoproteins occurring in milk and cheese. The group is characterized as one of the most nutritive milk proteins, containing all of the common amino acids and rich in the essential ones.	alpha-Casein,gamma-Casein,AD beta-Casein,Acetylated, Dephosphorylated beta-Casein,Casein,Casein A,K-Casein,Sodium Caseinate,alpha(S1)-Casein,alpha(S1)-Casein A,alpha(S1)-Casein B,alpha(S1)-Casein C,alpha(S2)-Casein,alpha-Caseins,beta-Casein,beta-Caseins,epsilon-Casein,gamma-Caseins,kappa-Casein,kappa-Caseins,AD beta Casein,Caseinate, Sodium,K Casein,alpha Casein,alpha Caseins,beta Casein,beta Caseins,beta-Casein Acetylated, Dephosphorylated,beta-Casein, AD,epsilon Casein,gamma Casein,gamma Caseins,kappa Casein,kappa Caseins
D003300	Copper	A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.	Copper-63,Copper 63
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012709	Serum Albumin	A major protein in the BLOOD. It is important in maintaining the colloidal osmotic pressure and transporting large organic molecules.	Plasma Albumin,Albumin, Serum
D015032	Zinc	A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.