Effect of Addition of Tryptophan on Aggregation of Apo-α-Lactalbumin Induced by UV-Light

Research output: Contribution to journal › Journal article › Research › peer-review

Standard

Effect of Addition of Tryptophan on Aggregation of Apo-α-Lactalbumin Induced by UV-Light. / Zhao, Zichen; Li, Renjie; Poojary, Mahesha M.; Nielsen, Søren B.; Lund, Marianne N.

In: Foods, Vol. 10, No. 7, 1577, 2021.

Research output: Contribution to journal › Journal article › Research › peer-review

Harvard

Zhao, Z, Li, R, Poojary, MM, Nielsen, SB & Lund, MN 2021, 'Effect of Addition of Tryptophan on Aggregation of Apo-α-Lactalbumin Induced by UV-Light', Foods, vol. 10, no. 7, 1577. https://doi.org/10.3390/foods10071577

APA

Zhao, Z., Li, R., Poojary, M. M., Nielsen, S. B., & Lund, M. N. (2021). Effect of Addition of Tryptophan on Aggregation of Apo-α-Lactalbumin Induced by UV-Light. Foods, 10(7), [1577]. https://doi.org/10.3390/foods10071577

Vancouver

Zhao Z, Li R, Poojary MM, Nielsen SB, Lund MN. Effect of Addition of Tryptophan on Aggregation of Apo-α-Lactalbumin Induced by UV-Light. Foods. 2021;10(7). 1577. https://doi.org/10.3390/foods10071577

Author

Zhao, Zichen ; Li, Renjie ; Poojary, Mahesha M. ; Nielsen, Søren B. ; Lund, Marianne N. / Effect of Addition of Tryptophan on Aggregation of Apo-α-Lactalbumin Induced by UV-Light. In: Foods. 2021 ; Vol. 10, No. 7.

Bibtex

@article{e99d52fee25c46c6bd8ed115a963f999,
title = "Effect of Addition of Tryptophan on Aggregation of Apo-α-Lactalbumin Induced by UV-Light",
abstract = "UV-B illumination facilitates aggregation of alpha-lactalbumin (alpha-LA) by intramolecular disulfide bond cleavage followed by intermolecular thiol-disulfide exchange reactions. However, long term exposure to UV-B illumination may induce undesired oxidative modifications of amino acid residues in the protein. The purpose of this study was to examine the effect of UV-induced aggregation of apo-alpha-LA (a calcium-depleted form of alpha-LA) under aerobic and anaerobic conditions and by addition of tryptophan (Trp) as a photosensitizer. The addition of Trp to apo-alpha-LA illuminated under anaerobic conditions facilitated the highest level of free thiol release and disulfide-mediated aggregation as compared to without addition of Trp under both anaerobic and aerobic conditions. Addition of Trp under aerobic condition resulted in the lowest level of free thiols and disulfide-mediated aggregation and the aerobic conditions caused oxidation of the free Trp with formation of kynurenine and 5-hydroxy-Trp. Minor levels of the Trp oxidation product, 3-hydroxy-kynurenine (2% converted from Trp), was formed in apo-alpha-LA with added Trp under both aerobic and anaerobic conditions after UV-B treatment.",
keywords = "UV illumination, tryptophan, aggregation, photooxidation, whey protein, EXCITED-STATE CHEMISTRY, AROMATIC-AMINO-ACIDS, WHEY PROTEINS, CYSTINE, PHOTOOXIDATION, PHOTOLYSIS, PEPTIDES, BONDS",
author = "Zichen Zhao and Renjie Li and Poojary, {Mahesha M.} and Nielsen, {S{\o}ren B.} and Lund, {Marianne N.}",
year = "2021",
doi = "10.3390/foods10071577",
language = "English",
volume = "10",
journal = "Foods",
issn = "2304-8158",
publisher = "MDPI AG",
number = "7",

}

RIS

TY - JOUR

T1 - Effect of Addition of Tryptophan on Aggregation of Apo-α-Lactalbumin Induced by UV-Light

AU - Zhao, Zichen

AU - Li, Renjie

AU - Poojary, Mahesha M.

AU - Nielsen, Søren B.

AU - Lund, Marianne N.

PY - 2021

Y1 - 2021

N2 - UV-B illumination facilitates aggregation of alpha-lactalbumin (alpha-LA) by intramolecular disulfide bond cleavage followed by intermolecular thiol-disulfide exchange reactions. However, long term exposure to UV-B illumination may induce undesired oxidative modifications of amino acid residues in the protein. The purpose of this study was to examine the effect of UV-induced aggregation of apo-alpha-LA (a calcium-depleted form of alpha-LA) under aerobic and anaerobic conditions and by addition of tryptophan (Trp) as a photosensitizer. The addition of Trp to apo-alpha-LA illuminated under anaerobic conditions facilitated the highest level of free thiol release and disulfide-mediated aggregation as compared to without addition of Trp under both anaerobic and aerobic conditions. Addition of Trp under aerobic condition resulted in the lowest level of free thiols and disulfide-mediated aggregation and the aerobic conditions caused oxidation of the free Trp with formation of kynurenine and 5-hydroxy-Trp. Minor levels of the Trp oxidation product, 3-hydroxy-kynurenine (2% converted from Trp), was formed in apo-alpha-LA with added Trp under both aerobic and anaerobic conditions after UV-B treatment.

AB - UV-B illumination facilitates aggregation of alpha-lactalbumin (alpha-LA) by intramolecular disulfide bond cleavage followed by intermolecular thiol-disulfide exchange reactions. However, long term exposure to UV-B illumination may induce undesired oxidative modifications of amino acid residues in the protein. The purpose of this study was to examine the effect of UV-induced aggregation of apo-alpha-LA (a calcium-depleted form of alpha-LA) under aerobic and anaerobic conditions and by addition of tryptophan (Trp) as a photosensitizer. The addition of Trp to apo-alpha-LA illuminated under anaerobic conditions facilitated the highest level of free thiol release and disulfide-mediated aggregation as compared to without addition of Trp under both anaerobic and aerobic conditions. Addition of Trp under aerobic condition resulted in the lowest level of free thiols and disulfide-mediated aggregation and the aerobic conditions caused oxidation of the free Trp with formation of kynurenine and 5-hydroxy-Trp. Minor levels of the Trp oxidation product, 3-hydroxy-kynurenine (2% converted from Trp), was formed in apo-alpha-LA with added Trp under both aerobic and anaerobic conditions after UV-B treatment.

KW - UV illumination

KW - tryptophan

KW - aggregation

KW - photooxidation

KW - whey protein

KW - EXCITED-STATE CHEMISTRY

KW - AROMATIC-AMINO-ACIDS

KW - WHEY PROTEINS

KW - CYSTINE

KW - PHOTOOXIDATION

KW - PHOTOLYSIS

KW - PEPTIDES

KW - BONDS

U2 - 10.3390/foods10071577

DO - 10.3390/foods10071577

M3 - Journal article

C2 - 34359447

VL - 10

JO - Foods

JF - Foods

SN - 2304-8158

IS - 7

M1 - 1577

ER -

ID: 275428064