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A COI"i?AI?ATIV:G S'l'UDY OF TH:S CJ�.S£IN I·liCELL:SS OF CAI-'RINE, OVI NE iU'ID BOVIN:E I1ILKS
A thes i s pr8sented in partial fulfilment
of the requirem ents for the degree of
Doc tor of }'hi losophy in rhys iology a-t
I'Ias s ey University.
Barry Charles Hichards6n
Novemb er , '1974
ll
Several oifferent hypotheses of casein micelle st ructure
hav8 been pro pos eQ from the data obt2ined in the investi�utions
carried out on micelles over the past twenty years. The present comparative st udy of c�princ (�oat) and ovine (sheep)
casein micelle sy:::otems v1ith that of the bovine 1:.'as made i?:l an
attempt to demonstrate the validi t�r of t;hos c ll;ypothcs cs.
The casein contents, minero.l levels, o_nd Ca:phosphate
ratios in the skim milks �aried between species, but no
significant differences in the Ca:phosphate r�tios in the
casein micelles or the sera were found. There were major dif-
ferences betv;een the electrophoretic p2tterns of the casein
saoples from the different sneci es. Both caprine and ovine
caseins cont�ined two prominent bands in the � -ca sein re gion ,
v1hile ca-orine casein nlso contained ;:1 snmller proportion of its
casein in more mobile components (ao-caseins) than the bovine. �)
Three major �-caseins were observed in ovine casein, and one
major a -casein in the mo_jorit;y of the caprine casein samy;les. s
Bovine, caprine a_nd ovine cuseins, isol ated from the
whole milks, were separated int o th eir major components by
ion exchane;e chromatography. The K-, (J-, c-J.nd a -cas eins s
which were isolated accounted for 15;j, 35;� and 50)j , respect-
ively of bovine casein, 10;;, 60'); and 2:;%, respectively of capri:te casein and 10�), Lt-5% and 35�;,s, res pect ively of ovine
cas ein . The caprine and ovine cas cins were identified as
�-, �- and K-type caseins by their chemical and physical
characteristics.
11he bovine, caprine and ovine K-cas eins v:ere readily
hydrolysed by rennin and were able to stabilize the Ca sensi
tive as- or ,8-cas eins. Caprine 131- and �2-cas eins which •.-:ere
present in equimolar amounts, had nearly identical amino acid
compositions, and Here similar to the.t of bovine t3-casein A2• The ,e1 component, however, contained an additional phosphate
residue.
11he temperatm'e dependent Ca sensitivities and the
temperature dependent polymerization of the cuprine � -ca s eins
were similar to that of bovine t3-cas ein. Hov1ever, � -casein
J..lJ..
app ear e d to as s ociat e more easily than ��-casein , des pi t e c
i t s higher net negative charge . Visc os ity measurement s indicated that the conformation of the two caprine �-caseins was s imilar t o that of b ovJ..ne �-cas ein , b o th at 4°C and at 25°C .
The maj or caprine a -cas ein was more s imi lar t o the s minor b ovine as3-cas e in than to bovine as 1 -cas ein. This was demons trat ed by their b eb.avi our on gel e l ectrophore s i s with Mg b uffers , C a s ens i tiviti es , amino aci d compos i t i ons a�d m o lecular wei ght s .
The two ovine �-cas eins were s imilar t o each other , and t o the caprine and b ovine �-cas eins . The relationship b etween the ovine �-cas eins was s imi lar to that of the caprine �-cas eins . Two of the thrE.e maj or ovine a -cas eins s were i s o l at e d . Thes e were both s imilar t o e ach o ther , and t o b ovine as1 -cas ein .
The proper t i e s o f t h e a -cas eins from the thr e e s peci e s s were mor e vari ab l e than tho s e of the f1-cas eins, which in turn were more variab l e than the K-cas e ins .
The cas ein mice l l es from caprine , ovine and bovine milks wer e all highly s o lvat ed and roughly s pherical . Alth ouc;h their s i z e distribut i ons varied , the micel l es were in each cas e compos ed of sub-unit s ab out 1 2 nm in diamet er . Gel chroma tography o f s ub -mice l l ar cas e in aggregat e s from the three s peci es indicat ed that they had s imi lar hydrodynamic s i z es and appear e d to b e in equi l ibrium Hith th eir component cas eins .
The finding that s imilar s ized sub-unit s ar e ·formed in the cas e in micel l es in the milks of the various s p eci es , s ugges t s that the di ffering proport i ons of the vari ous component cas eins must compens at e for the differ ences obs erv e d in t h e proper t i e s o f t h e cas eins . I t appeal'S l ikely that n o t enough emphas i s has b e en given t o the rol e of �-cas ein in micel l e s truct ur e , and �- and as -cas eins may b e int erchangeab l e .
I am grateful to the'fol lowing:
Professor H. E. I'1unford, for supervision and for the
collection of samples of sheep milk.
iv
Dr L.K. C reamer, ·N.l. Dairy Research Institute, for
guidance and continuing interest, and for obtainin� the
el ectron rnicror;raphs used in this thesis ( F.'igs .4.2 and 4.3 ) .
Dr K.N. Fearce, N.Z. Dairy Research Institute, for
measuring the cation concentrations and activities in the
milks.
Analytical Chemistry IJaboratory, N. 6. Dairy Hesearch
Institute, for Kjeldahl nitrogen determinations.
I"Ir B. Le ask, 'l'e Arakura, for supplying the goat milk.
Mrs A. Halligan, N.Z. Dairy Research Institute, for
assistance with the diagrams.
Mr C.K. Drew, r-lrs P.A. Leyland, l'iiss G . F . Evans and
Mr A.R. Matheson, N.3. Dairy Research Institute, for their
technical assistance at different p€�iods throughout the
course of the work.
I'Ty wife, Joy, for her considerabl e assistance during
the preparation of this thesis.
N .Z. Dairy Research Institute, for employment and the
use of the facilities during the course of the work.
.
'l'ABL.t.; 01•' C G.l�'l'LJ:LrS
CHAPl'ER 1 G:c.'NE.HAL INTHOlJUCTION
1 . 1 1 . 2
1 . 3
C omposi tion of Milk
The CG.seins
Aim of the Investigation
PAHT I A COI"'lf'A:RISON ·o:l!' CAPHI NE, OVI NE AND BOVINE MILKS Al�D 'rJ:fEIH CASEIN MICELLES
CHAPTER 3
2.1 2.2
2 . 3
C omposi t i on of Milk Size Dis tribution of Casein Mic ell es
Mol ecular Wei�1t of C as ein Mic elles
2.4 Voluminos ity and Solvat i on of
Cas ein Mic el l e s 2.5 Temperatur e Dependent Dis s oc i at ion
of Cas ein Mic el l es
EXFCRIMENT ... �L
3.3
Pr eparat ion of Skim l'1ilks
Nitrogen Distribution
InorGanic Phosphat e Det erminati on
3.4 Det ermination of Cat i on C onc entra
t i ons
3-5 3 . 6 3-7 3 . 8 3 . 9
Cat i on Act ivity
C itric Ac id C ont ents El ec trophores is
Fre e z e- etch El ec tron MicroGraphs \mo l e Mic e l l e Electron Mic ro graphs
3 . 1 0 Solvation o f Cas ein Mic el l e s :
Ultrac entrifugat i on
3 . 1 1 Solvat i on o f C as ein Mic el l es :
Page No .
1
1 1 4
7
8
8
9
1 1
1 1
1 2
1 4
1 4 1 4 1 5
1 5 1 5 1 6 1 6 1 6 1 6
1 7
Vis c os ity Measur ements 1 8 3 . 1 2 Temperatur e Dependent Dis s oc i at i on
of C as e in Mic ell es
3 . 1 3 Gel Chromatography of C�s ein
Mic e l l e s at 6°C and 37°C
20
Table of Cont2nts ( Contd.)
CHAPTER 4 CONPOBJI:PION OF C/JRINE, OVIN� AND
BOVIN:t; I'1ILKS
4 . 1 Nitrogen, Inorganic Phosphorus and
Citric Acid Contents
4 . 2 Cation Concentrations and Activities
Electrophoresis of the Caseins
Page No.
23
23 25 28
A COI'1PAR IS ON OI•' T HB PHOl-l�HTIES 01? THE CASEIN I''IICELLES 28
CHAPI'ER 5
4 . 4
4 . 6
4 . 7 4 . 8
Electron Micrographs of Intact
T'Iicelles
Electron Micrographs of Freeze-etch
I?.eplicas
Ultracentrifugation of Casein
I1icelles
Ca and Phosphate Distribution
Discussion
'fEI"ll-).t!:R,V11UHJ� DBFENDEJ:f'r IJRCPEH'l'IBS CF C J0SEI N
l'UCELLES
Ultracentrifugation
Voluminosity and Solvation of Casein
I'1icelles
5 . 3 Gel Chromatography of Bovine, Caprine
and Ovine Casein Micelles
5 . 4 Discussion
PART II ISOLATION AND CHARACTERIZATION OF THE I'1AJOR
CAFHINE AND OVINE CAS:EINS AND A COJ."lPARISON 1./ITH
THE BOVINE C ASEINS
CHAPT:ER 6 IN'rRODUCTION
BOVINE CASEINS
6 . 1 Historical
6 . 2 Identification of the Major Casein
Fractions
28
30
30 32 34
37
37
39
47
54
55
56
56
56
57
Tab l e of Cont ents ( C ontd . )
�;-CASEIN
.8-CASEI N
a -CASEINS s
6. 3
6 .4
6 .5
6 .6
6 .7
Genetic Variant of Bovine C as eins
I solation of �-Cas ein
Phys ical Properti es of K-C as ein Act i on. of Rennin on K-Cas ein
Nature o f the Carbohydrat e Residues
in K-C as ein
6 . 8 Amino Ac id C ompositiJn and Primary Struc ture of K-Cas ein
Page No .
58
61
61
6 3
6 3
64
64
68
6 .9 I s olation of #-Ca s e in 66
6 .10 Physical Properti es of /3-Cas eins 68
6 .11 Amino Ac i d Compos ition and Sequenc e of /3-C as ein 72
6 .12 �-Caseins 74
6 .13
6 .14
6 .15
6 .16
6 .17
I s o lat ion of as1 -Cas eins
Physical Properties of a -Cas e ins s Amino Aci d C ompos ition and Primary
Structur e of as 1 -C as eins
I-linor a -Cas eins s Homol o gi es Within the C as eins
6 .1 8 A Pos s ib l e Mechanism of Cas ein Fhosph0rylation
6 .19 Phylogenetic R e l at i onships of the Bovine Cas eins
75
75
'75
78
80
81
81
83
CASEINS FROM OTHER SPECIES 87
6 .20 C aprine Cas eins
6 .21 Ovine Cas eins
6 .22 Buffalo Cas eins
6 .2 3 Human C as eins
6 .24 Oth er Cas eins
87
89
9 3
93
96
Table of Cont.o�ts (Contd. )
EXrERI I'1ENrl'AL
7 . 1
7 . 2
7.3
7 • Lj.
7 -5
7.6
7 -7
7 . 8
7. 9
Preparation of Acid Caseins
Polymorphism in Caprine nnd Ovine
Casoins
Chromatography of Casein on DEAE-
Cellulose
Chromatography of Casein on CM-
Cellulose
Polyacrylamide Disc Gel Electro-
phoresis
Polyacrylamide .Slab Gel Llectro-
phoresis
Gel Electrophoresis in Buffers
Containing I'lg
�rotcolytic Degradation of Caseins
with Hennet
Holecular .Jeight of Caprine
K-Casein
7 . 1 0 f'Tolecular ·,/eight Ang_lysis in 6fi
Guanidine.HCl
Page No. 9 7
9 7
98
98
99
99
1 01
1 01
1 04
1 0 5
1 06
7 . 1 ·1 �lln.ino .:kid Compositions 1 08
7.1 2 �hosphorus 1 1 0 7.1 3 :t.xtinction Coefficients 1 1 0
7.1 4 Viscosity f'1easurements on Co.prine
and Bovine P-Caseins 1 1 1
7 . 1 5 Sedimentation Coefficients 1 1 3
7.1 6 Calcium Sensitivity of Caprine,
Ovine and Bovine Caseins 1 1 3
7 . 1 7 Temperature Dependent Polymeriza-
tion of p-Casein 1 1 4
CASEIN COl"lPOSITION AND ISOLA'riON OF THE
Cm'lEONENTS
8 . 1 Chromatography of \·ihole Bovine
Casein on DEAE-Cellulose
8.2 Composition of Bovine Casein
1 1 6
1 1 6
1 1 6
Table of Contents (Contd. )
8.3
8.4
8.5
8.6
8.7
8.8
Chromatography of ,,/hole Caprine
Casein on DE/LE-Cellulose
Composition of Caprine Casein
Chromatography of \Jhole Ovine
Casein on DElLE-Cellulose
Coriposition of Ovine Casein
Polymorphism in the Caprine Caseins
Polymorphism in the Ovine Caseins
CHAPTER 9 CHARACTERL�N.riON OF CAPRINE CASEINS
CAPRINl� K-CASEIN
9.1
9.2
Purification of Caprine K -Casein
Molecular Weight of Caprine
K-Cnsein
9.3 Amino Acid Composition of Caprine
9.4
CAFRINE �-CASEINS
9.5
9.6
9-7
9.8
CAPRINE a -CASEIN s
9.9
9.10
9.11
9.12
K-Casein
Discussion
Isolation of Caprine �1
- and
�2-Caseins
Molecular Weights of Caprine
t3-Cas eins
Amino Acid Compositions of the
Caprine �-Caseins and Bovine
�-Casein B Discussion
Isolation of the a -Caseins s
Molecular Weights of the
a -Caseins s Amino Acid Compositions of the
a -Caseins s
Discussion
Page No.
121
124
126
129
131
135
141
141
141
144
146
148
149
149
152
156
160
161
161
165
165
169
C HAPTER 10 C HJ�J�, CTEHI �ii.TION OF THE 11AJOR OVINE C 1\SLINS
10. 1 Ovine �<-Cas ein
OVI NE {3 -C ASEINS
10.2
10. 3
10.5
OVIN:t; a -CASEIN B s
10.6
10.7
10. 8
10.9
I so lation of Ovin8 {3-C as eins Molec ular We i ghts of Ovine {3-C as eins Amino Ac i d C ompos i t i ons of the Ovine {3-C as eins Disc us s i on
I s olat i on of Ovine as 2-C as e in and as 3- cas ein Mol ec ul ar i.·le ie;hts of Ovine a -C as eins s Amino Ac i d C ompos i t i ons of th e Ovine as -C as eins D i s c uss ion
CHAPTER 1 1 PHYSIC AL CHARACTERI L:;A.T I ON OF THE C AFRI NE , OVINB 1\ND l30VIN.F CASEINS
1 1.1
1 1.2
1 1.3
1 1.4
U l trac entrifugation Viscos i ty Heas ur em ents on the Caprine and Bovine p-C as e ins The Effect of Temperat ure on the S ol ubility of the C aprine , Ovine and Bovine p-C a s e ins in t t.e Pres enc e of CaC12 C alcium S ens i tivity of the C aprine , Ovine and Bovine C as eins Stab il i z at i on of the Caprine, Ovine and Bovine a - and s P-Cas e ins in the Pr es enc e 0f C aC12 by K-Cas eins
Page N o .
172
1?2
1 74
174
176
176
178
179
179
1 82
182
1 85
1 87
1 87
1 89
195
200
206
Table of Contents (Contd.)
CHAPrER 12
PART III
CHAFrEH 13
REF:ERENCES
11.6 Discussion
Page No.
208
A C Ol"lPAHI SON OF THE PROPERTIES OF
CASEINS FROM THE l"liLK OF SEVEHAL
SPECIES
12.1
12.2
12.3
12.4
«-Caseins
(J-Caseins
a -Caseins s Conclusions
I'lODELS OF BOVINE CASEIN l"IICELLE STRUCTURE
nND THZI H RELATI ONSHIP TO CAI--RINE AND
213
213
218
223
226
OVTNE CASEIN l"ITCELLES 228
DISCUSSI ON
13.2
13.3
13.4
13.5
13.6.
13.7
Hydrophobic, Electrostatic and
Hydrogen Bonding
Role of Disulphide Bonds
Colloidal Calcium Phosphate
Ccat-Core Models
Internal Structure I·lodels
Sub-unit Models
Caprine and Ovine Casein Micelles
and their Relationship to the
Models of Bovine Casein Micelle
Structure
229
229
231
231
232
233
233
235
241
1 .1
1 . 2
4.1
The C ompos i t i on of Ty�ic al Bovine Skim Mi lk
Appr oximat e C ompos it ion o f the Serum and
Mic e lle 1:-has es of Typic al Bovine Skim Mi lk
at 20°C
C ompos ition of Mi lks
4.2 Conc e ntrat i o ns and Ac t iv ities of C at i ons in Ski mmed Mi lk fr om .Animals of Several Spec i es
4 . 3 Vari ation of Cas ein-Pe llet So lvat i on and Dry
Pe lle t \Jeight with Spec i es and C entri fugation T i me
4 . 4 Dist ribution o f Calc ium and Inor ganic Phosphat e
Bet vJeen f'1i ce llar and S erum Phas e s
5 .3
5 • L�
7 . 1
7 .2
7.3
7.4 7-5
7.6
7-7 8.1 8.2
8.3
8.4
Temperat ur e Dep endent Dissoc iati on of C as ein
Nic e lles
Re la t i ve D ens i t i es of f''Jilks and Ultrac entri fuge
s era Intrins ic Vis c os ities and Volumino s i t i es of
C aprine , Ovine and Bovine Cas e in l''lic e lles
S o lvation of C as ein Mic e lles
Stock So lut i ons
Working So lut i ons
St ock Ge l S o lut i ons
Ac id Gel So lut ion ( pH 4)
Po lyacr ylamide Ge ls C o rtaining J"Ig
Standard Prot e ins
Locarte J.�ino Ac id Ana lys er Program C o mpos ition o f Bovine C as ein C omposition of C aprine C as ein C omposition o f Ovine C as ein
R e lative Elec trophore t ic Mobi li t i e s o f Some
Bovine , C aprine and Ovine C as eins in Alkaline
Page No .
2
3
24
26
3 2
3 3
3 7
40
44 46
1 00
1 00 1 02
102
1 03
1 07 1 09 1 20 1 25 1 3 0
Ge ls 1 34 9 .1 Amino Ac id C ompos itions of C aprine , Ovine and
Bovine K-C as e ins
9 .2
9.3
9 .4
Mo lec ular Vei ght s o f C aprine and Bovine Cas eins
Amino Ac id C o mpos itions of /3-C as e ins
R e lative Nob i lities of C as ein C omponents in th e
Pr es enc e and Abs enc e of f'lg
1 47
1 55 1 58
1 64
'rables ( Contd. )
9.5 Amino 1\cid Compositions of Caprine and Bovine
� -Cas eins
10.1
10.2
11.1
11.2
s P�ino Acid Compositions of the Ovine P-Caseins
Amino Acid Compos itions of the Ovine a -Caseins s Sedimentation Coefficients of Caprine P-Caseins
Intrinsic Viscosities of Caprine and Bovine
.8-Cas eins
11.3 Temperature of Half Trans ition Vo.lues for the P-Caseins
11.4 Stabilization of as- and P-Caseins by the
«-Cas eins
12.1 Amino 1\.cid Compositions of K-Cas eins from
Different Species
12.2
12.3
Amino Acid Compositions
Different Species
Amino Acid Compositions
Different Species
of P-Cas eins from
of a -Caseins from s
Page No.
168
177
184
188
194
196
207
217
222
225
FIGURES
Page No .
4 . 1 Alkaline gel elec trophoresis o f bovine , c aprine
and ovine c as eins
4 . 2 Typic al el ectron mic rographs of shadowed b ovine ,
29
ovine and c aprine c asein mic elles 31
4 . 3 Fre eze-etch el ectron mic rograrhs o f the c as ein
5 . 1
mic e l l es in bovine , ovine and caprine milk
Alkaline gel el ectrophoresis of the cas e ins pre s ent in the ultrac entrifuge s era , ob tained
31
from the milks at different t emperatur es 38
5.2 Reduc ed vis c o s i ty plots for c aprine cas ein
mic e l l es
5-3 Reduc ed vis c o s ity plots for ovine c as e in
mic el l es
5 . 4 Reduc ed vis c os ity plo t s for bovine c as ein mic el l es
5 . 5 Elution of ovine sub -mic ellar cas ein aggregates
41
42
43
from a Sephadex G-1 0-Sepharos e 4B c olumn at 37°C 49 5 . 6 Alkal ine gel e l ec tropho�esis o: frac tions
obt ained by g e l chromat ography of ovine large
cas e in mic elles at 37°C 50 5 . 7 Elut i on of c aprine sub-micellar c as e in aggr e gat e s
obt ained from a Sephadex G-1 0-Sepharos e 4B c o lumn at 6°C
5 . 8 Alkaline gel e l ec trophores is of frac t i ons obtained by gel chromatography of c aprine small
52
c as e in mic e l l e s at 6°C 53
6 . 1 Relative electrophore t i c mob ilities of the
6 . 2
6 . 3
6 . 4
6 . 5
6 . 6
genetic variants o f b o vine as1 - , P- and «-c as eins
at pH 8 . 6 and pH 3 . 0 59 Frimary s t ruc ture of b ovine «-c as e in B Primary struc tur e of b o vine (1-cas ein A2
Primary s t ruc ture of bovine CXg1 -cas eins Homol o gi es in the sequenc es of bovine as1- and fJ-c as e in
Fhylogeny o f the "gene c ompl exes" formed by the
all e l es of the bovine as 1 -Cn and �-Cn l o c i
The model for the organiz ation of the
as 1 -Cn-P -Cn- K-Cn " c lus t er of genes"
65 73 79
82
85
85
Fie;ures (Contd.)
Page No.
6 . 8 N-terminal sequences of bovine and ovine
K-casein A glycomacropeptides
6 . 9 Amino acid sequences of ovine and bovine
8 . 1
para- �-caseins
Chromatography of \tJhole bovine casein on DEAEcellulose
8 . 2 Alkaline gel electrophoresis of whole bovine
8 . 3
casein and the fractions isolated by chromato
graphy on DEAE-cellulose
Chromatography of whole caprine casein on
DEAE-cellulose
8 . 4 Alkaline gel electrophoresis of whole caprine
casein and the fractions isolated by chromato-
91
9 2
1 1 7
1 1 8
1 22
graphy on DEAE-cellulose 1 23
8 . 5 Chromatography of \vhole ovine casein on DEAE
cellulose
8 . 6 Alkaline gel electrophoresis of whole ovine
casein and the fractions isolated by chromato
graphy on DEAE-cellulose
8 . 8
�olyacrylamide zel electrophoresis (pH 8 . 4) of
samples of cap�ine casein
Polyacrylamide gel electrophoresis at pH 8 . 4
of samples of ovine casein from different
breeds
8.9 Polyacrylamide gel electrophoresis at pH 8 . 4 in
the presence of Mg of ovine caseins isolated
1 27
1 28
1 32
1 36
from different breeds of sheep 1 38
9 . 1 Chromatography of caprine K-casein on a CM
cellulose column
9 . 2 Alkaline gel electrophoresis of purified caprine
K-casein
9 . 3 Acid gel electrophoresis of purified caprine
K-casein
9 . 5
l''Iolecular weight calibration curve obtained
using a Sephadex G-1 00 column
Ch::r:'om2.toe;raphy of crude caprine p2-casein on
CI'1-c ell ulos e
1 42
1 43
1 43
1 45
1 50
fic;ures ( C ontd . ) Page No .
9 . 6 Alkal ine gel electrophores is of the c aprine
p -c as eins in the abs ence and pres enc e of MG
9 . '7 A typical run used t o calibrat e the mol ecular
weicht c o lumn
9 . 8 Mol ecular weie;ht calib ration curve obtained
1 51
1 53
us ing a Sepharos e 6B c olumn 1 54
9 . 9 Amino ac id analysis chromatogram obtained for
c aprine p2- c as ein ·us ing a Loc art e Hk.IV analys er 1 5'7
9 . 1 0 Alkal ine gel elec trophores is of pur i fi ed c aprine as -cas ein and purifi ed bovine as 3-c as ein in the pre s enc e and abs enc e o f Mg 1 62
9 . 1 1 Chrom�t ography of a s ample c ontaining the major
c aprine a - c as ein and b ovine a �-c as ein B on - S SI the molecular weight c o lumn to c ompare their mol ecular wei ghts 1 66
1 0 . 1 Alkal ine gel e l e c trophor e s i s o f purified ovine
K-cas ein and the effec t of r ennet on this
frac t ion 1 0 . 2 Alkaline gel e l e ctrophores is o f the purif i ed
ovine P-cas eins in the abs enc e o f pres enc e of Mg
1 0 . 3 Chromat ography of ovine as 3- c as e in on DEAE-
c e llulos e
1 0. 4 Alkaline gel el ec trophoresis o f the ovine
1 1 . 1 1 1 . 2
1 1 . 3
1 1 . 4
cxs-cas eins in the abs enc e and pres enc e o f I'Ig Reduc ed vis c o s i ty plots for c aprine p1 -cas ein Reduc ed vis c o s ity plots for c aprine p2-cas ein
Reduc ed vis c o s i ty plots for bovine p -c as ein A1
The eff ect o f t emperature and ionic strength on the turb i dity o f c aprine p1 -cas e in
s olut i ons
11 . 5 The effect of temperature and ionic s trength on
1 73
1 75
1 80
1 81 1 90
1 91 1 92
1 97
the turbidity o f c aprine p2-c as ein s o luti ons 1 98
1 1 . 6 The effect o f t emperature and ionic s tr ength
on the turb idity o f b ovine p-cas ein B s ol utions 1 99
1 1 . 7 C alc ium s ens i�ivity o f the caprine ��c a�eins at
37°C 201
:B,ip;ures (Contd. )
'11.8 Calcium sensitivity of the caprine, ovine and bovine �-caseins at 37°C
Page No.
202
1'1.9 Calcium sensitivity of the as-caseins at 37°C 20L�
'11.'10 Calcium sensitivity of the caprine, ovine und
bovine a -caseins at 37°C 205 s
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