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Intracellular Maturation of Acute Phase Proteins
Published in Andrzej Mackiewicz, Irving Kushner, Heinz Baumann, Acute Phase Proteins, 2020
Erik Fries, E. Mathilda Sjöberg
In 1984, Hille et al.78 reported that after the injection of [35S]sulfate into rats, labeled proteins could be detected in all tissues investigated, including blood plasma. Further analysis showed that the sulfate groups on proteins in tissues other than blood were linked mainly to carbohydrates, whereas those in plasma were linked mainly to tyrosine residues. Based on this and the earlier observation that certain secretory proteins contain sulfated tyrosines, they proposed that sulfate residues might have a function in protein secretion. However, reagents that could inhibit this modification showed that tyrosine sulfation was irrelevant to secretion.79 Tyrosine sulfation has been shown to take place in the trans-Golgi, apparently after sialylation.80,81
The Rous Sarcoma Virus Oncogene and its Proto-Oncogene Counterpart
Published in Pimentel Enrique, Oncogenes, 2020
A general sulfation of tyrosine residues on proteins has been observed in both normal and transformed cells. In contrast with the increase in phosphotyrosine induced by pp60v-src, a sometimes rather drastic reduction in tyrosine-O-sulfated proteins parallels infection of rat embryo fibroblasts (cell line 3Y1) with either RSV or FSV.163 The decrease in tyrosine-O-sulfate occuring in cells infected with these acute transforming retroviruses is apparently due to increased secretion of compounds containing tyrosine-O-sulfate, possibly including a loss of fibronectin (which contains sulfate) from the cell membrane coincident with malignant transformation.163,164 The relationship between tyrosine phosphorylation and tyrosine sulfation, if any, remains to be identified.
Reactivities of Amino Acids and Proteins with Iodine
Published in Erwin Regoeczi, Iodine-Labeled Plasma Proteins, 2019
No other plasma protein is known at present to contain sulfated tyrosyls, yet fibrinogen is by no means a unique protein to have such a residue. The single tyrosyl (Tyr-12),in the heptadecapeptide, gastrin, is available either nonsulfated (gastrin I) or sulfated (gastrin II), each form being capable of stimulating gastric acid secretion.270 Cerulein, a decapeptide from an amphibian (Hyla caerulea) in South America and Australia, also contains one sulfated tyrosine.271 Cerulein possesses a potent hypotensive action and it stimulates extra- vascular smooth muscle. Fibrinopeptide B (bovine or human) sensitizes the rat uterus to bradykinin-induced contractions;272 probably it also reduces vascular permeability in various pathological conditions, like the carrageenan edema, the inflammatory response to X-ray irradiation, delayed immunological reactions, and experimental allergic encephalomyelitis.273 It would be premature to speculate whether the occurrence of O-sulfated tyrosines in biologically active peptides is a sheer coincidence. This whole area of research may soon undergo a rapid development in view of the recent discovery that tyrosine sulfation is a widespread phenomenon among cellular proteins. According to Huttner,274 sulfated tyrosyls are present in proteins from a variety of cultured cells (adrenal, brain, muscle cells, fibroblasts, etc.) as well as in all organs obtained from the rat after in vivo labeling with 35S.
In silico prediction of post-translational modifications in therapeutic antibodies
Published in mAbs, 2022
Tyrosine sulfation is an enzymatic modification that is catalyzed by tyrosylprotein sulfotransferases (TPSTs). During sulfation, a sulfate group is attached to the hydroxyl group of tyrosine residues.111 Tyrosine sulfation has been reported for a few monoclonal and bispecific antibodies.111–114 Sulfation of mAbs can occur in Chinese hamster ovary (CHO) cells during the cell culture. The degree of tyrosine sulfation in CHO cells varies due to differential expression of phosphoadenosine-5ʹ-phosphosulfate (PAPS) synthetase and TPST. PAPS synthetase converts ATP to PAPS; TPST transfers the sulfo group from PAPs to tyrosine residues.115 Sulfation in mAbs generates acidic variants,111 but the impact of tyrosine sulfation on the safety and efficacy of therapeutic antibodies has not yet been established.5