{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n Gamma‐glutamyltransferase (GGT) enzymes play multifaceted roles in cell physiology by regulating glutathione metabolism, maintaining redox balance, and modulating extracellular matrix assembly. Several studies indicate that GGT activity is central to detoxification processes and may influence disease progression. On one hand, GGT‐mediated cleavage of extracellular glutathione is critical for sustaining cellular antioxidant capacity, and transition‐state analogue inhibitors have been developed that potently and irreversibly block GGT activity, pointing to novel therapeutic approaches to overcome chemoresistance and oxidative stress–related damage."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": " In addition, GGT isoforms expressed at the cell surface—including those released in exosomes—have emerged as promising noninvasive biomarkers; for instance, increased exosomal GGT1 activity correlates with prostate cancer progression, underscoring its potential diagnostic utility."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": " Moreover, elevated serum GGT levels associate with aggressive tumor behavior and poorer clinical outcome in hepatocellular carcinoma patients, suggesting that circulating GGT may also serve as an important prognostic indicator."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": " In a related context, distinct GGT activity arising from collagen‐modifying enzymes—such as the galactosylhydroxylysyl glucosyltransferase function of lysyl hydroxylase 3—is indispensable for proper glycosylation of collagen, basement membrane formation, and embryonic development."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Taken together, these findings support a model in which members of the GGT family – including pseudogene derivatives such as GGT2P, which are thought to be involved in fine tuning enzyme activity and regulation—may contribute not only to intracellular antioxidant defense and extracellular matrix integrity but also serve as biomarkers of disease severity. Although the precise biological roles of GGT2P remain to be fully elucidated, emerging evidence suggests it could modulate glutathione homeostasis and impact tumor progression by influencing both redox status and cellular microenvironments.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Liyou Han, Jun Hiratake, Akane Kamiyama, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Design, synthesis, and evaluation of gamma-phosphono diester analogues of glutamate as highly potent inhibitors and active site probes of gamma-glutamyl transpeptidase."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Biochemistry (2007)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1021/bi061890j"}], "href": "https://doi.org/10.1021/bi061890j"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "17260973"}], "href": "https://pubmed.ncbi.nlm.nih.gov/17260973"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Kyojiro Kawakami, Yasunori Fujita, Yoko Matsuda, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Gamma-glutamyltransferase activity in exosomes as a potential marker for prostate cancer."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "BMC Cancer (2017)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1186/s12885-017-3301-x"}], "href": "https://doi.org/10.1186/s12885-017-3301-x"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "28476099"}], "href": "https://pubmed.ncbi.nlm.nih.gov/28476099"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Shun-Jun Fu, Qiang Zhao, Fei Ji, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Elevated Preoperative Serum Gamma-glutamyltranspeptidase Predicts Poor Prognosis for Hepatocellular Carcinoma after Liver Transplantation."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Sci Rep (2016)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/srep28835"}], "href": "https://doi.org/10.1038/srep28835"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "27381639"}], "href": "https://pubmed.ncbi.nlm.nih.gov/27381639"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Heli Ruotsalainen, Laura Sipilä, Miia Vapola, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Glycosylation catalyzed by lysyl hydroxylase 3 is essential for basement membranes."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Cell Sci (2006)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1242/jcs.02780"}], "href": "https://doi.org/10.1242/jcs.02780"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "16467571"}], "href": "https://pubmed.ncbi.nlm.nih.gov/16467571"}]}]}]}