Heat stabilization produced by protein-protein association. A differential scanning calorimetric study of the heat denaturation of the trypsin-soybean trypsin inhibitor and trypsin-ovomucoid complexes.

Donovan, John W.; Beardslee, R A

doi:10.1016/s0021-9258(19)41670-0

Cited by 76 publications

(8 citation statements)

References 22 publications

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“…Thus, if an endothermic event accompanies or precedes the heat-induced aggregation reaction, then this transition is either too weak or too broad to be detected by our instrument. There are a number of precedents for protease-protease inhibitor complexes melting at higher temperatures than either component separately (Chlebowski & Williams, 1983;Takahashi & Sturtevant, 1981;Zahnley, 1979Zahnley, ,1980Donovan & Beardslee, 1975). In the present case, stabilization appears to have been sufficient to shift the major melting transitions beyond the accessible range.…”

Section: Discussionmentioning

confidence: 59%

Changes in protein conformation and stability accompany complex formation between human C1 inhibitor and C1.lovin.s

Lennick¹,

Brew²,

Ingham³

1985

Biochemistry

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The fluorescence spectrum of C1 inhibitor (C1-Inh) in aqueous buffer has a maximum at 324 nm which shifts to 358 nm in 6.0 M guanidinium chloride (GdmC1), indicating that fluorescent tryptophans are buried in the native protein. When titrated with GdmC1, the fluorescence intensity, polarization, and emission maximum of C1-Inh and C1-s exhibited clear transitions which were more prominent than those of the enzyme-inhibitor complex. Two of the variables (intensity and emission maximum) suggest biphasic unfolding of C1-Inh. Differential absorption measurements and sodium iodide quenching of intrinsic fluorescence were consistent with a net increase in the exposure of tryptophans and tyrosines upon complex formation. This reaction, i.e., complex formation, was also accompanied by an increase in the ability to enhance the fluorescence of the hydrophobic probe 8-anilino-1-naphthalenesulfonate. Fluorescence assays of heat denaturation showed transitions at 40 and 52 degrees C for C1-s and at 60 degrees C for C1-Inh whereas there was no detectable melting transition for the complex. Similarly, differential scanning calorimetric measurements revealed transitions at 42, 52, and 62 degrees C for C1-s and one transition at 60 degrees C for C1-Inh, with no major transitions detectable for the complex. The ratio of the calorimetric enthalpy to the apparent van't Hoff enthalpy for thermal unfolding of C1-Inh was 1.6. Taken together, these results suggest that C1-Inh and C1-s are each composed of at least two independently unfolding domains and that complex formation, which involves conformational change, yields a protein substantially more stable than either component alone.

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Section: Discussionmentioning

confidence: 59%

Changes in protein conformation and stability accompany complex formation between human C1 inhibitor and C1.lovin.s

Lennick¹,

Brew²,

Ingham³

1985

Biochemistry

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“…The technique of scanning calorimetry has been increasingly applied over the last 10 years in studies of thermal transitions in proteins [reviewed by Privalov (1947)] and in investigations of stability changes of proteins caused by specific interaction with metal ions (Donovan & Ross, 1975), by complex formation (Donovan & Ross, 1973;Donovan & Beardslee, 1975), and by change in conformation (Donovan & Mapes, 1976). We have used scanning calorimetry in this investigation to measure the increase in denaturation temperature of several proteins in the presence of various sugars and polyols-an effect apparently related to changes in solvent properties and * From the CSIRO Division of Food Research, Food Research Laboratory, North Ryde, N.S.W.…”

mentioning

confidence: 99%

Increased thermal stability of proteins in the presence of sugars and polyols

Back¹,

Oakenfull²,

Smith³

1979

Biochemistry

731

380

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Sugars and polyols stablize proteins against heat denaturation. Scanning calorimetry was used to obtain a quantitative estimate of the degree of stabilization. Solutions of ovalbumin, lysozyme, conalbumin, and alpha-chymotrypsinogen were heated at a constant rate, and the temperature of the maximum rate of denaturation was estimated (Tm). Addition of a sugar or polyol raised Tm. The magnitude of the stabilizing effect (delta Tm) depended on both the nature of the protein and the nature of the sugar or polyol, ranging from 18.5 degrees C for lysozyme at pH 3 in the presence of 50% (w/w) sorbitol to 0 degrees C for conalbumin at pH 7 in 50% glycerol solution. It is argued that this stablization is due to the effects of sugars and polyols on hydrophobic interactions. The strength of the hydrophobic interaction was measured in model systems in sucrose and glycerol solutions. Sucrose and glycerol strengthened the pairwise hydrophobic interaction between hydrophobic groups; however, they reduced the tendency for complete transfer of hydrophobic groups from an aqueous to a nonpolar environment. The extent of stabliziation by different sugars and polyols is explained by their different influences on the structure of water. The difference between the partial molar volume of the sugar or polyol and its van der Waals volume was used as a rough quantitative measure of the structure-making or structure-breaking effect. There was a linear relationship between this quantity and delta Tm.

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“…There are relatively few calorimetric studies of protein-protein interaction. For trypsin with soybean trypsin inhibitor or with ovomucoid (Donovan & Beardslee, 1975), the T¿ for the complex was greater than for either component. The Tn subunit interactions appear to produce a complex in which the thermal stability is intermediate between the components rather than greater than either component.…”

Section: Resultsmentioning

confidence: 84%

“…There are only a few complex protein systems which have been studied. Only one thermal transition has been observed for trypsin with soybean trypsin inhibitor or ovomuccoid (Donovan & Beardslee, 1975) and for lactic dehydrogenase (Jacobson & Braun, 1977). It appears that when the interaction between subunits is strong dissociation and denaturation occur simultaneously and only AG°¡ (kcal mol"1) -1.7 ± 0.2 -2.2 ± 0.1 -9.1 -15.6 -24.2 -34.3 -44.4…”

Section: Discussionmentioning

confidence: 99%

Thermal denaturation of beef cardiac troponin and its subunits with and without calcium ion

Jacobson¹,

Devin²,

Braun³

1981

Biochemistry

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Heat stabilization produced by protein-protein association. A differential scanning calorimetric study of the heat denaturation of the trypsin-soybean trypsin inhibitor and trypsin-ovomucoid complexes.

Cited by 76 publications

References 22 publications

Changes in protein conformation and stability accompany complex formation between human C1 inhibitor and C1.lovin.s

Changes in protein conformation and stability accompany complex formation between human C1 inhibitor and C1.lovin.s

Increased thermal stability of proteins in the presence of sugars and polyols

Thermal denaturation of beef cardiac troponin and its subunits with and without calcium ion

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