Tripeptide glutathione

Many substances which are necessary (and even essential) for life functions contain sulphur for example, the amino acids cysteine and methionine, the tripeptide glutathione or coenzyme A (CoA), with the latter containing the SH group of cys-teamine as the terminal functional group. CoA acts as a coenzyme in all important biochemical acylations. The cysteamine SH group bonds to carboxylic acids to give thioesters ... 

Hydrophilic peptides and proteins are frequently large molecules they may enter the brain by carrier-mediated transport, receptor-mediated transcytosis, or by adsorptive-mediated transcytosis. Small peptides, such as di- and tripeptides are transported by the specific transporters, PepTl and PepT2, but neither of them is present at the BBB. Nevertheless, there is saturable brain uptake of the tripeptide glutathione and of several opioid peptides, suggesting that specific transporters, as... 

The tripeptide glutathione is the major intracellular antioxidant. The tripeptide glutathione (y-glutamyl-cysteinyl-glycine) is the major intracellular antioxidant. It is synthesized via these reactions (Fig. 40-6) ... 

The tripeptide glutathione (y-L-Glu-L-Cys-Gly) may play a role in the transport of Bi(III) in the body. The complex [Bi(SG)3] is very stable (log K 29.6) over a wide pH range (2-10) with binding via the S atom only (465). Exchange of GSH between free and bound forms is relatively rapid at physiological pH (ca. 1500 s 1). 

The toxicity of isocyanates is the distant consequence of their reactivity as electrophiles toward alcohols, phenols, amines, and thiols [112]. These are, indeed, the mechanisms by which isocyanates react with and modify proteins and nucleic acids [113][114], Isocyanates also react reversibly with the tripeptide glutathione (GSH), the resulting conjugates being considered to be transport forms as well as products of detoxification [115] [116]. 

All is not doom and gloom, however, in that nature has provided in our bodies an alternative nucleophile to react with stray electrophiles like Michael acceptors. This rather important compound is the tripeptide glutathione, a combination of glutamic acid, cysteine, and glycine (see Box 6.6). 

Peroxides, including hydrogen peroxide (H2O2), can damage cells by causing unwanted oxidation reactions. The tripeptide glutathione (GSH) is able to participate in a cellular protection mechanism via its ability to form disulfide bridges. 

The glutathione transferases (GST), together with the tripeptide glutathione (GSH), conjugate the highly reactive and potentially... 

The amino acids believed to be involved in GTF are the constituents of the naturally occurring tripeptide glutathione (256). Anderson et al. have reported a complex of glutathione/nicotinic acid and chromium(III) to be particularly active in their in vitro assay.1198 The complex was described as being purified by HPLC, but the details of the preparation are not available. 

Biological Hydrolysis of Alkyl Halides with Glutathione. One widespread hydrolysis approach used by organisms involves the use of the tripeptide, glutathione (GSH) ... 

Almost all cells contain a high concentration (3-9 mM) of the thiol-containing tripeptide glutathione (G-SH, Box 11-B). In its disulfide form it participates in forming disulfide bridges in secreted extracellular proteins (Eq. 10-9) via intermediate mixed disulfides. Mixed disulfides with glutathione as well as with other thiols can also be formed within cells by oxidative... 

Activation of amino acids for incorporation into oligopeptides and proteins can occur via two routes of acyl activation. In the first of these an acyl phosphate (or acyl adenylate) is formed and reacts with an amino group to form a peptide linkage (Eq. 13-4). The tripeptide glutathione is formed in two steps of this type (Box 11-B). In the second method of activation aminoacyl... 

Synthetic peptide inhibitors have been developed for a variety of proteases [199-204]. Peptide inhibitors of the metalloprotease angiotensin I converting enzyme (ACE) are of major importance as hypertensive agents [13, 31]. A variety of peptides derived from protease-catalyzed hydrolysis of com cc-zein [202-203] or of wheat germ protein [199, 204] inhibit ACE (Table 6). The most potent of such plant-derived ACE inhibitory peptides is Ile-Val-Tyr (IVY) (Ki 0.1 xM) [199, 204], Further plant-derived peptide ACE inhibitors include the tripeptide glutathione [73, 82], the glutathione -related peptide Y-L-glutamyl-(+)-allyl-L-cysteine sulphoxide [73, 82, 200, 201] and the tripeptide His-His-Leu (HHL) from fermented soybean [201] (Table 6). 

The S-containing tripeptide glutathione (GSH) is present in cells at mM concentrations, and the formation of Pt GSH complexes may play an important role in the biological activity of platinum complexes. By multinu-... 

The 13C spectmm of the tripeptide glutathione at neutral pH in H2O solution has four signals in the 160-180 ppm region. When the spectrum is acquired in a 1 1 H20 D20 mixture, two of the signals become apparent doublets. Explain why. 

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