Analysis of major proteins and fat fractions associated with mare's milk fat globules

Abstract

Although several studies have aimed to identify mare's milk proteins, only the major whey proteins and some caseins have yet been characterized. Incomplete sequencing of the equine genome and the difficulty of recovering highly hydrophobic proteins mean that little is known to date about the proteins associated with milk fat globules, which have been shown to play an important role in newborns' defense mechanisms. The fat fraction, in particular the distribution of unsaturated fatty acids, has been more extensively studied, but complex lipids are only partially elucidated. This study reports a 2-DE approach combined with a powerful method for de novo protein sequencing, and quali-quantitative data on complex lipid composition determined by high performance TLC (HPTLC) and GC. The presence in mare's milk of long-chain highly unsaturated fatty acids, and the evidence of close similarity between equine and human milk fat globule membrane proteins, support the use of mare's milk for human nutrition.

Identification of Equine Lactadherin-derived Peptides That Inhibit Rotavirus Infection via Integrin Receptor Competition

“…1). The two-dimensional electrophoresis map showed a pattern very similar to that previously published for horse MFGM proteins, where lactadherin was the major protein and was identified in several spots at different molecular masses (34). The spots 1-4, corresponding to the molecular masses of horse lactadherin, were excised, and the proteins were identified by MALDI-TOF MS and PMF as the horse milk fat globule-EGF factor 8 splice variant, also known as horse lactadherin (Table 1).…”

“…When separated by two-dimensional electrophoresis, each of these proteins shows an apparent molecular mass above the theoretical value, with the difference due to glycosylation (29 -31). MFGM-associated proteins from water buffalo, sheep, and horse also have been analyzed (32)(33)(34). Comparative species-to-species structural studies among MFGM proteins showed high variation, especially for lactadherin (35).…”

Fatty Acid Composition, Fat Globule Size and Reactive Oxygen Species-Scavenging Activity of Mare Milk: A Longitudinal Study

“…As a matter of fact, on day 1 fat globules are slightly over 3 µm but thereafter they show a lower dimension, between 2 and 3 µm, as reported also by Malacarne et al [9]. HM fat globules have an average diameter of 4µm [1] while for CM it is of 3-5 µm. Dimension of fat globules are very important for lipid digestion by human pancreatic lipase (hPL) as discovered by Berton et al [13].…”

Characterization of sheep milk fat globule proteins by two-dimensional polyacrylamide gel electrophoresis/mass spectrometry and generation of a reference map

“…However, while the major protein components of milk have been the subject of intense research and characterization, less abundant milk proteins and peptides have lagged behind, and studies have been mostly performed in humans and bovines. In recent years, however, the study of the milk fat globule membrane protein component is receiving growing interest (Aoki, 2006;Barello et al, 2008;Bianchi et al, 2009;Cebo, Caillat, Bouvier, & Martin, 2010;Charlwood et al, 2002;Mather, 2000;Reinhardt & Lippolis, 2006).…”

“…Major MFG proteins (MFGPs) from human and bovine milk have been extensively characterized and reviewed (Mather, 2000) and several proteomic studies on MFGPs have been recently published for bovine, equine, and buffalo milk (Barello et al, 2008;D'Ambrosio et al, 2008;Reinhardt & Lippolis, 2006), while the MFGPs of small ruminants have been subjected to significantly less intense research efforts. Moreover, the two-dimensional polyacrylamide gel electrophoresis (2-DE) reference maps of sheep and goat MFGPs are not currently available.…”