Effect of temperature/ethanol on the secondary structure of bovine Apo Alpha-Lactalbumin investigated by FTIR/2D IR correlation spectoscropy
Why this work is in the frame
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Bibliographic record
Abstract
Whey proteins play a vital role in the manufacture of food products due to their nutritional value and versatile functional properties.-Lactalbumin (-LA) is the second most abundant protein in bovine whey and the most abundant protein of human whey.-LA is a low-molecular-weight (14.2 kDa) and acidic (pI 4-5) protein that is produced in the lactating mammary glands and has a role in lactose biosynthesis.BAMLET/HAMLET (bovine/human alpha-lactalbumin made lethal to tumor cells) are complexes of -LA and oleic acid that have been shown to have cytotoxic effects on tumor cells but not on healthy cells.In vitro, it has been reported that BAMLET-type complexes can be prepared by heating a solution of bovine apo (calciumdepleted) -LA in sodium phosphate buffer to which an ethanol solution of oleic acid has been added.However, the possibility that the presence of ethanol may facilitate the complexation of oleic acid with -LA by affecting the thermal denaturation of the protein has not been investigated In the present study, the combined effects of ethanol and temperature on the secondary structure of bovine apo -LA were examined by variable-temperature Fourier transform infrared (VT-FTIR) spectroscopy in conjunction with Fourier self-deconvolution (a resolution enhancement technique) and two-dimensional cross correlation spectroscopy (2D CCS).At room temperature, an increase in -helical and -structure content at the expense of 3 10 -helices and turns was observed as a function of increasing the concentration of ethanol (from ~2.5 to 33% w/v).These findings are consistent with the fluorescence and proteolysis studies of -LA reported in the literature, which showed a similar effect of ethanol on the secondary structure of -LA.Subjecting bovine apo -LA solutions to a heating-cooling cycle (heating from 25 to 95 0 C and cooling from 95 to 25 0 C) in the presence of varying concentrations of ethanol was found to alter the protein's secondary structure.At any concentration of ethanol the -helix and 3 10 -helices of the secondary structure of bovine apo -LA were lost upon heating of the protein.The sequences of the changes in secondary structure during the heating and cooling cycles were elucidated by 2D CCS.The results revealed that the protein refolded during the cooling cycle by reversal of the sequence of unfolding events during the heating cycle only in the presence of 20% or higher concentration of ethanol.Overall, the present study supported the ethanol-induced reversible thermal denaturation of bovine apo--LA.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.002 | 0.004 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it