Elhaj and Freigoun, IJAVMS, Vol. 9, Issue 2, 2015: 41-45

Camel’s Milk Protein Fractionation by SDS-Polyacrylamide Gel

Electrophoresis Ahmed Elemam Elhaj, Somaya Freigoun

Shahra University and Institute for Studies and Promotion of Animal Export- University of Khartoum,

Sudan

Corresponding author email: AHELMAM@YAHOO.COM

Abstract

This study was designed to fractionate, identify and quantify Camel’s Milk proteins and whey

proteins by using the technique of gel Electrophoresis. Experimental study. Polyacrylamide gel

electrophoresis in sodium dodecyl sulphate (SDS-PAGE) was carried out using a Bio-Rad, Mini Protean

II apparatus (Bio-Rad Laboratories Hercules, California 94547, USA). Treated and untreated casein

samples of camel milk were separated using a polyacrylamide gel. The study resulted in that; the casein

was fractionated into α-casein, β-casein and κ- casein. While the whey proteins were fractionated into α -

lacto albumin and β-latoglobulins. The fractionation of protein from one day to one week of lactation was

very difficult while during lactation from over one week to sixteen weeks the α-casein band was medium,

β- casein was high, and κ-casein was very low. On the other hand, the casein fractionation during 32

weeks to 48 weeks of lactation, the α-casein and β-casein were in high concentration while the κ-casein

was very low or absent. Also, the α – lactalbumin band was medium and the β -lactoglobulins appear

absent in whey protein. In conclusion the absence of β-lg in camel milk leads to make it as

suitable.Substitution for children allergic to bovine milk protein because β-lg is the main causativeagent

for allergy from bovine milk.

Key-words:

Camel’s Milk, Protein, Fractionation, Electrophoresis

Introduction

Camel’s milk is rich in proteins which are classified into two main classes, major milk proteins including

caseins α, βand k-caseins and two whey proteins, α-lactalbumin and β-lactoglobulin. Also minor milk

proteins including lysozyme, lactoferrins, lactoperoxidase and immunoglobulin. The colostrum is rich in

immunoglobulins and serum albumin, whereas levels of casein and α-LA were relatively low and

increased gradually until the average values reached the levels of regular milk. It is shown that, there is

lack of β-LG in the camel’s milk [1]

. Halima et.al[2]

reported that,the main components of whey proteins in

camel milk and colostrum were similar to that in bovine, except for the lack in β -lactoglobulin.On

analysis of small proteins in camel’s milk, the camel α-lactalbumin structure was determined. It was then

discoveredthat α -lactalbumin preparations, after the first purification step of exclusion chromatography,

contain additional proteins with special properties.One of these proteins, corresponding to a major non-

lactoalbumin component [3]

. Casein is a major part of protein in camel milk. Milk of dromedary camel

contains protein ranged from 2.15 to 4.90 percent [4]

and has 1.63 to 2.76 percent casein protein that

Camel’s Milk Protein Fractionation by SDS-Polyacrylamide Gel Electrophoresis

Elhaj and Freigoun, IJAVMS, Vol. 9, Issue 2, 2015: 41-45

constitutes 52 to 87 percent of total milk protein, whey protein constitutes 20 to 25 percent that make it

the second biggest fraction of protein and whey protein in range of 0.63 and 0.80 percent [5,6]

.

Camel milk β-lactoglobulin is found in traces, while α-lactalbumin comprises the major camel milk

portion. In the milk of bovines, α-lactalbumin constitute only 25 percent, while β-lactoglobulin made 50

percent of the total whey protein that make it the major whey protein of bovine milk[7]

Materials and Methods

Protein Fractionation of Camel’s Milk by

(SDS-Polyacrylamide Gel Electrophoresis. (SDS-PAGE)

Polyacrylamide gel electrophoresis in sodium dodecyl sulphate (SDS-PAGE) was carried out

using a Bio-Rad, Mini Protean II apparatus (Bio-Rad Laboratories Hercules, California 94547, USA)

according to Laemmli[8]

. Treated and untreated casein samples of camel milk were separated using a

polyacrylamide gel.

Results

1.Proteins fractionationbyElectrophoresis(In four phases of lactation)

The gel electrophoresis techniques were used to fractionate proteins of camel’s milk and also

identification and quantification of milk proteins and whey proteins. The casein was fractionated and

analyzed into α-casein, β-casein and κ-casein,and the whey proteins of camel milk werefractionated into

α – lactalbuminand β -latoglobulins as shown in Figure (1).

2.Protein fractionation during period from (one day to one week )

The fractionation of protein during this period is very difficult.

3.Protein fractionation during period from (over one week to 16 weeks )

The results were shows in Figure (1).The α-casein band was medium, β-casein was high, and κ-

casein was very low.while, the α –lactalbumin band was mediumand the β -latoglobulins appears absent

in whey protein.

4.Protein fractionation during periodfrom (over 16 weeks to 32 weeks of lactation).

The results were shows in Figure (1).The bands concentration of α-casein, β-casein and κ-casein

were similar at the phase of one week to 16 weeks. While, the band of α – lactalbumin is medium and

also the β -latoglobulins appears absent in wheyprotein.

5.Protein fractionation during periodfrom (32 weeks to 48 weeks of lactation)

The results were shows in Figure (2).The milk casein was fractionated into α-casein, β-casein and κ-

casein. The bands of α-casein and β-casein were high compared with others phases of lactation.

Camel’s Milk Protein Fractionation by SDS-Polyacrylamide Gel Electrophoresis

Elhaj and Freigoun, IJAVMS, Vol. 9, Issue 2, 2015: 41-45

Figure (1) protein fractionation during period from (over one week to 16 weeks) &(16-32 weeks

Figure (2)

protein

fractionati

on during

period

from (over

32 weeks

to 48

weeks )

Absent of β -Latoglobulins

1*

2*

3*

1

2

3

D C A: Casein 1-16 weeks. B: (Casein 16-32 weeks. C: whey protein 1-16 weeks. D: whey protein from 16-32 weeks .

1: α-casein / 2: β-casein / 3: κ-casein of (1-16 weeks) 1*: α-casein / 2*: β-casein / 3*: κ-casein of ( 16-32 weeks)

B A

Camel’s Milk Protein Fractionation by SDS-Polyacrylamide Gel Electrophoresis

Elhaj and Freigoun, IJAVMS, Vol. 9, Issue 2, 2015: 41-45

Discussion

The result of present study validate the result of the FAO research, which reported by Ramet [9]

.So the

present study showed that the kappa casein is very weak and has low band during electrophoresis in all

phases of lactation.( As shown in Figure (1and 2).On the other hand, the camel’s milk is characterized by

the absence of β- lactoglobulin similar as in human milk [9]

. Inthe present study the camel’s milk contains

no β- lactoglobulin, in all phases of lactation as shown in theFigure (1) &Figure (2). While, Merinet al(10)

reported that, the proteins of camel’s milk are the decisive components for preventing and curing food

allergies because camel’s milk contains no β-lactoglobulin. The camel’s milk non contains any amount of

β- lactoglobulin, and has a different beta-casein .In 1989, Beg et al(11)

found that the camel’s milk has a

different beta-casein, that is responsible for allergies. Therefore, the β- lactoglobulin and a beta-casein are

responsible for allergies in cow milk. The present study results are in agreement with those reported by

Merinet al[10]

and Beget al[11]

. Moreover, in some countries the camel’s milk used as therapeutic food,

because it has especial elements characterized of high nutritive values. In particular, camel’s milk, which

is consumed in many countries (such as Kazakhstan) for its medicinal virtues, is renowned for being

richer in some lactoproteins compared with cow’s milk. In fact, the concentrations of Lf and IgG in

camel’s milk seem to be only slightly higher than those in other milks [12]

. In the present study the the

fractionation of protein during one week is very difficult While during the period from over one week to

sixteen weeks of lactationthe band of α-casein was medium, β-casein was high, and κ-casein was very

low. The concentration of α – lactalbumin was medium and the β -latoglobulins appears absent in whey

protein. On the other hand, in the present study the casein fractionation during 32 weeks to 48 weeks of

lactation α-casein , β-casein were in high concentration while the κ-casein was very weak or absent.

According to Merinet al [10]

it was shown in colostrum and milk that most camel serum proteins are

similar in molecular weights to bovine whey proteins. The main differences between the serum protein

samples are the lack of β -lg and the high amount of camel serum albumin. Moreover, the different

proportion of the various proteins. Camel colostrum is rich in IgG and camel serum albumin, which are

reduced in amount already after 3 days postpartum. The main protein in whey of camel colostrum is

camel serum albumin while that of whey of bovine colostrum is β -lg. In the present study the results

were variable during four phases of lactation. The present results agreed with that reported by Halima et

al., [2]

inthat, the main components of whey proteins in camel milk and colostrum were similar to that in

bovine, except for the lack in β -lactoglobulin.

In conclusion that the absence of β-lg in camel milk lead to make it as suitable substitution for

children allergic to bovine milk protein because β-lg is the main causative agent for allergy from bovine

milk.

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