title: Through the eye of an electrospray needle: mass spectrometric identification of the major peptides and proteins in the milk of the one-humped camel (Camelus dromedarius).
abstract: The milk of the one-humped camel (Camelus dromedarius) reportedly offers medicinal benefits, perhaps because of its unique bioactive components. Milk proteins were determined by (1) two-dimensional gel electrophoresis and peptide mass mapping and (2) liquid chromatography-tandem mass spectrometry (LC-MS/MS) following one-dimensional polyacrylamide gel electrophoresis. Over 200 proteins were identified: some known camel proteins including heavy-chain immunoglobulins and others exhibiting regions of exact homology with proteins from other species. Indigenous peptides were also identified following isolation and concentration by two strategies: (1) gel-eluted liquid fraction entrapment electrophoresis and (2) small-scale electrophoretic separation. Extracts were analyzed by LC-MS/MS and peptides identified by matching strategies, by de novo sequencing and by applying a sequence tag tool requiring similarity to the proposed sequence, but not an exact match. A plethora of protein cleavage products including some novel peptides were characterized. These studies demonstrate that camel milk is a rich source of peptides, some of which may serve as nutraceuticals.
authors.affiliation: Department of Pharmacology, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Abdulqader
authors.initials: A
authors.lastname: Alhaider
authors.forename: Abdel Galil
authors.initials: AG
authors.lastname: Abdelgader
authors.forename: Abdullah Arif
authors.initials: AA
authors.lastname: Turjoman
authors.forename: Keri
authors.initials: K
authors.lastname: Newell
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Hunsucker
authors.forename: Baozhen
authors.initials: B
authors.lastname: Shan
authors.forename: Bin
authors.initials: B
authors.lastname: Ma
authors.forename: David S
authors.initials: DS
authors.lastname: Gibson
authors.forename: Mark W
authors.initials: MW
authors.lastname: Duncan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002162:Camelus; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D008894:Milk Proteins / Q000032:analysis* / Q000737:chemistry / Q000145:classification; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis* / Q000737:chemistry / Q000145:classification; D010449:Peptide Mapping / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D008894:Milk Proteins; D010446:Peptide Fragments
keywords: Camelus dromedarius; DIGE; camel milk; mass spectrometry; peptides; proteins; proteomics