Abstract
The process of activation converts protein sulfhydryl (SH) groups from the masked state to a free state with increased reactivity. Beta-lactoglobulin (beta-Lg) SH group activation was measured, in phosphate buffer (pH 6.8) using K-casein 2-thio, 5'-nitrobenzoic acid (Cn-Ellman), at 412 nm. Reaction transition state parameters from 25-55degreesC and 60-80degreesC were not significantly different. Present results were compared with differential scanning calorimetry (DSC) traces for beta-Lg heat unfolding, temperature-reaction profiles for whey or beta-Lg heat aggregation, and also SH-activation in skim milk. The findings reveal that SH-group activation precedes heat unfolding and aggregation of beta-Lg. Further studies using protein disulfide reagents such. as Cn-Ellman will help to elucidate the mechanism of SH group activation for beta-Lg.
Original language | English |
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Pages (from-to) | 195-200 |
Journal | International Dairy Journal |
Volume | 14 |
Issue number | 3 |
Publication status | Published (in print/issue) - Mar 2004 |
Bibliographical note
Reference text: 1. ANEMA SGReaction kinetics of thermal denaturation of whey proteins in heated reconstituted whole milk
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 44 : 422 1996
2. APENTEN RKO
Protein stability function relations: beta-lactoglobulin-A sulphydryl group reactivity and its relationship to protein unfolding stability
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES 23 : 19 1998
3. APENTEN RKO
Is the rate of sulfur-disulfide exchange between the native beta-Lactoglobulin and PDS related to protein conformational stability?
INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 34 : 483 1999
4. APENTEN RKO
Protein stability function relations: native beta-lactoglobulin sulphhydryl-disulphide exchange with PDS
JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 80 : 447 2000
5. APENTEN RKO
Thermodynamic parameters for beta-lactoglobulin dissociation over a broad temperature range at pH 2.6 and 7.0
THERMOCHIMICA ACTA 359 : 181 2000
6. BUROVA TV
What may be bovine beta-lactoglobulin Cys121 good for?
INTERNATIONAL DAIRY JOURNAL 8 : 83 1998
7. DEJONG P
Impact and control of fouling in milk processing
TRENDS IN FOOD SCIENCE & TECHNOLOGY 8 : 401 1997
8. DEJONGH HHJ
Mild isolation procedure discloses new protein structural properties of beta-lactoglobulin
JOURNAL OF DAIRY SCIENCE 84 : 562 2001
9. ELLMAN GL
TISSUE SULFHYDRYL GROUPS
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS 82 : 70 1959
10. ELLMAN GL
A COLORIMETRIC METHOD FOR DETERMINING LOW CONCENTRATIONS OF MERCAPTANS
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS 74 : 443 1958
11. EUBER JR
INTERACTION OF KAPPA-CASEIN WITH IMMOBILIZED BETA-LACTOGLOBULIN
JOURNAL OF DAIRY SCIENCE 65 : 2384 1982
12. FARRELL HM
Environmental influences on purified kappa-casein: Disulfide interactions
JOURNAL OF DAIRY SCIENCE 81 : 2974 1998
13. GALANI D
Beta-lactoglobulin denaturation by dissociation-coupled unfolding
FOOD RESEARCH INTERNATIONAL 32 : 93 1999
14. HAE DJ
DISULFIDE BOND FORMATION BETWEEN THERMALLY DENATURED BETA-LACTOGLOBULIN AND KAPPA-CASEIN IN CASEIN MICELLES
JOURNAL OF DAIRY SCIENCE 73 : 900 1990
15. HARLAND HA
A QUANTITATIVE EVALUATION OF CHANGES OCCURRING DURING HEAT TREATMENT OF SKIMMILK AT TEMPERATURES RANGING FROM 170-DEGREES TO 300-DEGREES-F
JOURNAL OF DAIRY SCIENCE 38 : 1199 1955
16. HUTTON JT
THE ORIGIN OF SULFHYDRYL GROUPS IN MILK PROTEINS AND THEIR CONTRIBUTIONS TO COOKED FLAVOR
JOURNAL OF DAIRY SCIENCE 35 : 699 1952
17. JOCELYN PC
CHEMICAL-REDUCTION OF DISULFIDES
METHODS IN ENZYMOLOGY 143 : 246 1987
18. KITABATAKE N
Reversible conformational change in beta-lactoglobulin A modified with N-ethylmaleimide and resistance to molecular aggregation on heating
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 49 : 4011 2001
19. KOKA M
SPECTROPHOTOMETRIC METHOD FOR DETERMINATION OF HEAT-ACTIVATED SULFHYDRYL GROUPS OF SKIMMILK
JOURNAL OF DAIRY SCIENCE 51 : 217 1968
20. LAEMMLI UK
CLEAVAGE OF STRUCTURAL PROTEINS DURING ASSEMBLY OF HEAD OF BACTERIOPHAGE-T4
NATURE 227 : 680 1970
21. LARSON BL
CEREAL CHEM 26 : 287 1949
22. LYSTER RLJ
FREE + MASKED SULPHYDRYL GROUPS OF HEATED MILK + MILK POWDER + NEW METHOD FOR THEIR DETERMINATION
JOURNAL OF DAIRY RESEARCH 31 : 41 1964
23. PRABAKARAN S
Thermal unfolding of beta-lactoglobulin: Characterization of initial unfolding events responsible for heat-induced aggregation
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 45 : 4303 1997
24. RASMUSSEN LK
THE MULTIMERIC STRUCTURE AND DISULFIDE-BONDING PATTERN OF BOVINE KAPPA-CASEIN
EUROPEAN JOURNAL OF BIOCHEMISTRY 207 : 215 1992
25. RASMUSSEN LK
Disulphide-linked caseins and casein micelles
INTERNATIONAL DAIRY JOURNAL 9 : 215 1999
26. REINER CK
ANAL BIOANAL CHEM 373 : 266 2002
27. ROEFS SPFM
A MODEL FOR THE DENATURATION AND AGGREGATION OF BETA-LACTOGLOBULIN
EUROPEAN JOURNAL OF BIOCHEMISTRY 226 : 883 1994
28. SAKAI K
Conformation and stability of thiol-modified bovine beta-lactoglobulin
PROTEIN SCIENCE 9 : 1719 2000
29. SINGH H
IN-VITRO DIGESTIBILITY OF WHEY PROTEIN/KAPPA-CASEIN COMPLEXES ISOLATED FROM HEATED CONCENTRATED MILK
JOURNAL OF FOOD SCIENCE 58 : 299 1993
30. TAYLOR MJ
ANTIOXIDANT ACTIVITY OF SKIM MILK - EFFECT OF HEAT AND RESULTANT SULFHYDRYL-GROUPS
JOURNAL OF DAIRY SCIENCE 63 : 1783 1980
Keywords
- beta-Lactoglobulin
- sulfhydryl activation
- heat aggregation
- kappa-casein
- milk protein