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.

Comparison of the hypoglycemic and antithrombotic (anticoagulant) actions of whole bovine and camel milk in streptozotocin-induced diabetes mellitus in rats

“…Thus, the reversal of a similar hemostatic activation process by camel milk in the STZ rat model can only be explained by the effect of bioactive antithrombotic components present in ingested camel milk, in the same manner as the bovine milk reported in the literature and discussed above. However, camel milk biological properties have attracted attention only, recently and its detailed composition has been reported by our group (Alhaider et al, 2013).…”

“…The identified camel milk proteins and peptides displayed homology with bovine peptides encoded in the backbone of major proteins; others were characterized by de novo sequencing of tandem mass spectra (Alhaider et al, 2013). Similar to bovine milk, some of the camel milk peptides are certain to display (in addition to antiplatelet/antithrombotic effects) antimicrobial properties, antifungal properties, blood pressure-lowering effects, cholesterol-lowering effects, and immunomodulatory effects (Park and Haenlein, 2013;Baheti et al, 2014;Aref, 2018), as has already been established for bioactive peptides isolated from bovine milk.…”

Novor: Real-Time Peptide de Novo Sequencing Software

“…Since MS/MS data size has grown tremendously, today’s de novo sequencing analyses are carried out more often with computer software than by a human expert. Among its many applications, de novo sequencing has been used to sequence endogenous peptides [ 1 , 2 ], characterize mutations in antibodies [ 3 ], perform proteomics analysis for organisms with no or incomplete protein databases [ 4 – 6 ], and to help sequence an entire protein [ 7 – 10 ].…”

Camel milk ameliorates the coagulopathy in streptozotocin diabetic rat model

“…Additionally, in our recent report (Alhaider et al . ), CM was found to be rich in immunoglobulins and a diverse array of peptides encrypted within milk proteins. Some of these peptides were identified by homology with bovine peptides encoded within the backbone of major proteins and are certain to display antimicrobial and antifungal properties, blood pressure‐lowering effects, cholesterol‐lowering, antithrombotic and immunomodulatory effects, as has already been established in bioactive peptides isolated from bovine milk.…”