Characterization of γ‐glutamyltranspeptidases from dormant garlic and onion bulbs

Sun, Yangying; Hu, Jing; Wang, Weidong; Zhang, Bin; Shen, Yingbin

doi:10.1002/fsn3.820

Cited by 10 publications

(4 citation statements)

References 28 publications

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“…Therefore, while we are able to detect significant levels of VvGGT3 transcript in the total RNA isolated from mature berry pulp, we are not able to comment on the levels of active protein in these tissues. GGTs are known to accumulate in certain storage tissues such as seed and bulbs (Balakrishna and Prabhune, 2014; Sun et al, 2019). When stored at cool temperatures below 20°C, GGT activity has been detected in the bulbs of garlic and onion.…”

Section: Discussionmentioning

confidence: 99%

Functional Characterization of the Grapevine γ-Glutamyl Transferase/Transpeptidase (E.C. 2.3.2.2) Gene Family Reveals a Single Functional Gene Whose Encoded Protein Product Is Not Located in Either the Vacuole or Apoplast

2019

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γ-glutamyl transferases/transpeptidases (E.C. 2.3.2.2, GGTs) are involved in the catabolism of many compounds that are conjugated to glutathione (GSH), which have a variety of roles. GSH can act as storage and transport vehicle for reduced sulfur; it is involved in the detoxification of xenobiotics and also acts as a redox buffer by utilizing its thiol residue to protect against reactive oxygen species, which accumulate in response to biotic and abiotic stress. Furthermore, many distinctive flavor and aroma compounds in Sauvignon blanc wines originate from odorless C5- and C6-GSH conjugates or their GGT catabolized derivatives. These precursors are then processed into their volatile forms by yeast during fermentation. In many plant species, two or more isoforms of GGTs exist that target GSH-conjugates to either the apoplast or the vacuole. A bioinformatics approach identified multiple GGT candidates in grapevine (Vitis vinifera). However, only a single candidate, VvGGT3, has all the conserved residues needed for GGT activity. This is intriguing given the variety of roles of GSH and GGTs in plant cells. Characterization of VvGGT3 from cv. Sauvignon blanc was then undertaken. The VvGGT3 transcript is present in roots, leaves, inflorescences, and tendril and at equal abundance in the skin, pulp, and seed of mature berries and shows steady accumulation over the course of whole berry development. In addition, the VvGGT3 transcript in whole berries is upregulated upon Botrytis cinerea infection as well as mechanical damage to leaf tissue. VvGGT3-GFP fusion proteins transiently over-expressed in onion cells were used to study subcellular localization. To confirm VvGGT3 activity and localization in vivo, the fluorescent γ-glutamyl-7-amido-4-methylcoumarin substrate was added to Nicotiana benthamiana leaves transiently over-expressing VvGGT3. In combination, these results suggest that the functional VvGGT3 is associated with membrane-like structures. This is not consistent with its closely related functionally characterized GGTs from Arabidopsis, radish and garlic.

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Section: Discussionmentioning

confidence: 99%

Functional Characterization of the Grapevine γ-Glutamyl Transferase/Transpeptidase (E.C. 2.3.2.2) Gene Family Reveals a Single Functional Gene Whose Encoded Protein Product Is Not Located in Either the Vacuole or Apoplast

2019

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“…It dropped below 4.2 after the rst week of aging due to carboxylic acids that formed during thermal processing by browning reaction [38]. The effect of high temperature and acidity may inhibit γ-GTP activity because the optimum pH and temperature for γ-GTP activity are pH 6 and 70 °C [39]. Therefore, samples treated with high temperatures (80 °C) have less SAC content than at low temperatures.…”

Section: Principal Component Analysis Of Black Garlic Qualities During Heat Treatmentmentioning

confidence: 99%

The Shortest Innovative Process of Black And Golden Garlic For Enhancing The S-Allylcysteine Content And Antioxidant Activity

Pakakaew

Phimolsiripol

Taesuwan

et al. 2022

Preprint

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Black garlic is a type of heat-treated garlic for which the traditional process is extremely simple but it is very time-consuming, taking more than one month. The purpose of this research was to reduce the processing time of black garlic. A novel processing including soaking and freezing was applied for the pre-treatment of the garlic. The effects of two temperatures (60 and 80 °C) and two relative humidities (65 and 80% RH) were investigated to find the optimum conditions for black garlic production. The optimum conditions for black garlic production were pre-treatment using CaCl2 soaking followed by freezing before being further incubated at 80 °C and 80% RH for 1 week. This optimal condition produced black garlic with high antioxidant activity as 5,390 and 25,421 mg Trolox/100 g dry weight for DPPH and ABTS assays, respectively. However, the incubation process at 60 °C and 65% RH provided golden garlic with the highest S-allylcysteine (SAC) content by about 1,772 mg/100 g dry weight. This novel process shortened the processing time of black garlic by about four times and provided a new processed garlic product called “golden garlic”.

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“…GGT activity in AGE is detectable even after 300 days, although its activity is weak (10). Sun et al reported that GGT activity derived from garlic was significantly enhanced by glucose (Glc), aspartic acid (Asp) and cysteine (Cys) (15). Saccharides in raw garlic are mainly fructans that are composed of 1-2 glycosyl linkage polymer of fructose (Fru) with the reduction end of Glc (Fig.…”

Section: S-alk(en)ylcysteinesmentioning

confidence: 99%

Chemistry of aged garlic: Diversity of constituents in aged garlic extract and their production mechanisms via the combination of chemical and enzymatic reactions (Review)

et al. 2019

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Raw garlic contains characteristic compounds, such as S-alk(en)ylcysteine sulfoxides, γ-glutamyl-S-alk(en)ylcysteines and polysaccharides. These compounds undergo various transformation processes during the aging process. Among these compounds, the change of sulfur-containing molecules is diverse and time-dependent. Previously, by means of the liquid chromatography (LC)/LC-mass spectrometry (MS) method, a number of unidentified peaks corresponding to candidates of sulfur-containing molecules were detected in the chromatogram of aged garlic extract (AGE), and identified using MS and nuclear magnetic resonance (NMR). The production mechanisms of these compounds were then examined by model reactions and laboratory experiments mimicking the aging process. Three γ-glutamyl tripeptides [γ-glutamyl-γ-glutamyl-S-methylcysteine, γ-glutamyl-γ-glutamyl-S-allylcysteine (GGSAC), γ-glutamyl-γ-glutamyl-S-1propenylcysteine], γ-glutamyl-S-allylmercaptocysteine (GSAMC) and cis-S-1-propenylcysteine (cis-S1PC) were isolated and identified. GGSAC was produced from GSAC through the enzymatic reaction catalyzed by γ-glutamyltranspeptidase (GGT), and two other tripeptides could be produced in similar reactions. GSAMC was produced by the reaction between γ-glutamyl dipeptides and allicin. Furthermore, GSAMC was a precursor compound of S-allylmercaptocysteine (SAMC), and thus it was produced from GSAMC by GGT. cis-S1PC was produced from trans-S1PC by the isomerization reaction. A number of other compounds were also identified, including Maillard reaction products; however, their production mechanisms have not been elucidated. In this review, we present the changes in characteristic constituents in raw garlic and garlic extract during the aging process and discuss their production mechanisms involving the various chemical and enzymatic reactions.

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Characterization of γ‐glutamyltranspeptidases from dormant garlic and onion bulbs

Cited by 10 publications

References 28 publications

Functional Characterization of the Grapevine γ-Glutamyl Transferase/Transpeptidase (E.C. 2.3.2.2) Gene Family Reveals a Single Functional Gene Whose Encoded Protein Product Is Not Located in Either the Vacuole or Apoplast

Functional Characterization of the Grapevine γ-Glutamyl Transferase/Transpeptidase (E.C. 2.3.2.2) Gene Family Reveals a Single Functional Gene Whose Encoded Protein Product Is Not Located in Either the Vacuole or Apoplast

The Shortest Innovative Process of Black And Golden Garlic For Enhancing The S-Allylcysteine Content And Antioxidant Activity

Chemistry of aged garlic: Diversity of constituents in aged garlic extract and their production mechanisms via the combination of chemical and enzymatic reactions (Review)

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