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Title of Thesis

Obaid Ullah Beg
Institute/University/Department Details
University of Karachi/ H.E.J Research Institute of Chemistry
Number of Pages
Keywords (Extracted from title, table of contents and abstract of thesis)
camel milk, proteins, a-lactalbumin, c-type lysozymes, acidic protein, neurpohysins, antiproteases, peptide, k-casein

The present study was undertaken to characterize camel milk whey proteins. The main objective has been the isolation, purification and structure elucidation of protein components in whey, which comprise known classes of milk proteins as well some undefined proteins. The study resulted in the characterization of a-lactalbumin (related to c-type lysozymes), whey acidic protein (a cysteine rich protein-related to neurpohysins, antiproteases and some other biologically active peptides), and a fragment of B-casein (a praline rich peptide with relationship to opioid like peptides). A brief account of the proteins studied is given below.


The complete amino acid sequence of camel milk a-lactaloumin was determined by analyses of the intact protein, the CNBr fragments and the enzymatic peptides obtained from the carboxymethy protein. Results show that the protein consists of 123 amino acid residues with a quite homologous to other characterized a-lactalbumins but also exhibit extensive differences: 35 residues are conserved in hitherto known a-loctal-bumins with characterized structures. All residues important for structural or functional roles are conserved in camel a-lactalbumin.

1.2Whey acidic protein.

A protein (M 14 kDa) rich in Cysteine/½ cystine has been isolated from camel milk by exclusion charomatography and reverse-phase high performance liquid chromatography. The complete amino acid sequence of this protein has been determined by the analyses intact protein and peptides obtained form CNBr, trypsin, glu specific protease and cleavage after tryptophan residue from the carboxymethylated protein. The protein has 16 cysteines in a total of 117 amino acid residues corresponding to 8 disulphide bridges.

Comparision of the protein with some other proteins reveals interesting relationships: (1) the protein is homologous to previously reported rat and mouse protein, (ii) it shows a region with postulated phosphoserines in relation to a- and B caseins; (iii) demonstrate some similarities to neurophysins and antileukoprotease in half cysteine and internal repeat pattern and to a domain of red sea turtle protease inhibitor and (iv) superficial similarities to insuline family and to some other biologically active proteins are observed.

1.3The results identify the protein as a member of whey acidic proteins classified in the family of “Four disulphide core” proteins and extend suggestions of relationships with various proteins involed in binding or interacting functions.A B-casein Fragment ( a protine rich peptide form camel milk)

A camel milk protein has been purified by reverse phase HPLC. The protein is rich in praline (25% of the whole protein). The N-terminal amino acid sequence shows that the protein is homologous with a C-tertminal region of B-caseins from other species. The protein is concluded to be fragment of B-casein derived form non-trytic type of cleavage of the parent molecule.

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S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
80.79 KB
2 1 Summary
23.39 KB
  1.1 A- Lectalbumin (I)
  1.2 Whey Acidic Protein (II)
  1.3 A B-Casein Fragment (A Praline Rich Peptide Form Camel Milk ) (III)
3 2 Introduction 1
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  2.1 General Classification Of Milk Proteins 1
  2.2 Non-Classified Proteins 2
  2.3 A-Lactalbumin 2
  2.4 B-Lactoglobulins 9
  2.5 Milk Whey Acidic Proteins 11
  2.6 Processed Fragments And Peptides Of B-Casein 13
  2.7 Fragments Of K-Casein 15
  2.8 Miscellaneous Milk Proteins 16
4 3 Material And Methods 17
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  3.1 Treatment Of Milk 18
  3.2 Purification Of Proteins 18
  3.3 Sodiumdodecylsulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE ) 20
  3.4 N-Terminal Determination By Dansyl -Chloride Method 21
  3.5 Modification Of Proteins 22
  3.6 Chemical Cleavages 23
  3.7 Enzymatic Cleavage 24
  3.8 Peptides Purification 24
  3.9 Amino Acid Analysis 25
  3.10 Amino Acid Sequence Analysis Of Proteins And Peptides By Double Coupling DABITC Method (Appendix II ) 26
  3.11 Monitoring Of Radio Activity 27
5 4 Results 28
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  4.1 Purification Of Camel Milk Whey Proteins 28
  4.2 A-Lactablumin From Camel Milk 28
  4.3 Camel Milk Whey Acidic Protein 43
  4.4 A Praline Rich Peptide In Camel Milk Corresponds To A B-Casein Fragment 53
6 5 Discussion 62
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  5.1 A-Lactalbumin Form Camel Milk 62
  5.2 Whey Acidic Protein Form Camel Milk 69
  5.3 A B-Casein Fragment (A Praline Rich Peptide From Camel Milk 85
  5.4 Milk Proteins Evolutionary Aspects 90
7 6 References 93
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  6.1 Appendix I (One And Three Letter Symbols Of Amino Acids ) 101
  6.2 Appendix-II (Double Coupling Manual Sequencing Method ) 102