The Modification of Arginine
Roger L. Lundblad, Claudia M. Noyes in Chemical Reagents for Protein Modification, 1984
Of particular interest has been the observations of Fonda and Cheung29 that the reaction of arginine with phenylglyoxal is greatly accelerated in bicarbonate-carbonate buffer systems. Figure 13 shows the reaction of phenylglyoxal with N-acetylarginine, A’-acetyllysine and N-acetylcysteine in 0.083 M sodium bicarbonate, pH 7.5. Reaction is only seen, for all practical purposes, with the arginine derivative. L-Arginine reacted in the same manner suggesting that modification of the α-amino group did not occur under these conditions. Figure 14 compares the rate of reaction of phenylglyoxal with arginine in bicarbonate buffer with that in other buffer systems (borate, Veronal, /V-efhylmorpholine). The reaction appears to be first order with respect to bicarbonate (Figure 15). The reaction of methylglyoxal with arginine is also enhanced by bicarbonate (Figure 16) while a similar effect is not seen with either glyoxal or 2,3-butanedione. The molecular basis for this specific buffer effect is not clear at this time nor is it known whether reaction with α-amino functional groups occurs at a different rate than with other solvent systems used for this modification of arginine with phenylglyoxal. Feeney and co-workers10 reported that p-nitrophenylglyoxal (prepared from p-nitroacetophenone — see Reference 31) reacts with arginine in 0.17 sodium pyrophosphate — 0.15 M sodium ascorbate, pH 9.0 to yield a derivative which absorbs at 475 nm. There is also reaction with histidine (the imidazole ring is critical for this reaction in that the 1-methyl derivative yielded a derivative which absorbed at 475 nm while the 3-methyl derivative did not). Free sulfhydryl groups also yielded a product with absorbance at 475 nm, but its absorbance was only 3% of that of the arginine. Branlant and co-workers32 have used p-carboxyphenyl glyoxal in bicarbonate buffer at pH 8.0 to modify aldehyde reductase. Saturation kinetics were noted with the use of this reagent.
Lysinuric protein intolerance
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop in Atlas of Inherited Metabolic Diseases, 2020
Lysine depletion may be improved with supplemental L-lysine-HCl (0.05–0.5 mmol/kg, three times per day) [58], but this is limited by malabsorption and intestinal tolerance. ɛ-N-Acetyllysine has been shown to increase plasma concentrations of lysine [59]. Increase may also be accomplished by the IV administration of lysine [60].
Metabolic Modifications of Histones
Lubomir S. Hnilica in The Structure and Biological Function of Histones, 1972
More than a decade ago, it was discovered that proteins can have their NH2-terminal amino acid acetylated. Acetyl NH2-terminal groups were found in tobacco mosaic virus protein, ovalbumin, cytochrome C, etc. In 1963, Phillips222 reported that the NH2-terminal amino acids in histone fractions F1 (I) and F2a (F2al or IV and F2a2 or IIb 1) were acetylated. Later, he substantiated his findings by the isolation of the NH2-terminal acetyl peptides from the calf thymus histone fractions F2al (IV) and F2a2 (IIb2).272 It became obvious, however, that if histone acetylation was to play any significant role in genetic restriction, it could not be limited to the acetylation of only the terminal amino acid residues. Even before the determination of the complete amino acid sequence of the F2al (IV) histones from calf thymus and pea seedlings, which established unequivocally the presence of labile acetyl groups on certain lysine residues, Gershey et al.284 and Vidali et al.667 reported that calf thymus histone fractions F2al (IV) and F3 (III) contained appreciable amounts of metabolically labile acetate. The fraction F2a2 (IIbl) had only a small amount of labile acetate, while histones F1 (I) and F2b (IIb2) did not contain any. The labile acetate sites were labeled with acetate-1-C14 by incubation of the isolated nuclei in vitro. All of the labeled acetate was found in the form of ∊-N-acetyllysine. Pogo et al.668,669 used 2 M neutral hydroxylamine to differentiate between NH2- and O-acetyl groups in rat liver histones. Only amino-bound acetyl was found in fractions F2al (IV) and F2a2 (IIb2), but both NH2- and O-acetyls were present in F3 (III) histone. ∊-N-acetyllysine was also found in the F3 (III) fraction and, in only minute amounts, in F2a2 (IIbl) histone. The existence of labile O-acetyl groups in the F3 (III) histone was also reported by Nohara et al.,670,671 who used partially purified pigeon liver enzyme for the in vitro acetylation of histones, and by Gallwitz and Sekeris,672 who used intact isolated rat liver nuclei. In contrast to the above, Vidali et al.667 did not find any O-acetyl-C14 incorporated into F3 (III) histones during the incubation of isolated thymocyte nuclei with labeled acetate.
Roux-en-Y gastric bypass surgery in Zucker rats induces bacterial and systemic metabolic changes independent of caloric restriction-induced weight loss
Published in Gut Microbes, 2021
Florian Seyfried, Jutarop Phetcharaburanin, Maria Glymenaki, Arno Nordbeck, Mohammed Hankir, Jeremy K Nicholson, Elaine Holmes, Julian R. Marchesi, Jia V. Li
Urinary profiles of the Sham-BWM group presented a tight clustering of all time points, while Sham-obese and RYGB groups shifted dramatically, forming three distinctive clusters representing each experimental group (Figure 3c and S3B). There was no significant difference in the urinary profiles between Sham-BWM and Sham-obese at any time points (Table S1). In contrast, metabolic differentiation RYGB and Sham-obese or Sham-BWM was observed over all post-surgical time points (Figs S6-S7). The concentrations of TCA cycle intermediates (e.g., citrate, 2-oxoglutarate, succinate, fumarate and malate) were lower in RYGB compared with Sham groups, whereas the host-microbial co-metabolites including indoxyl sulfate (IS), 4-hydroxyphenylacetate, 4-cresyl glucuronide and phenylacetylglycine (PAG) were higher (Figure 3d). Urinary levels of 2-oxoisovalerate, the breakdown products of branched chain amino acid (BCAA), valine, were found to be higher in RYGB than in Sham animals. However, 3-methyl-2-oxovalerate, a breakdown product of isoleucine, was lower in RYGB compared to Sham-obese. Furthermore, Nε-acetyllysine, N-acetylalanine and Nα-acetyllysine were found to be lower in RYGB.
Related Knowledge Centers
- Acetylation
- DNA
- Epigenetics
- Histone
- Histone Acetyltransferase
- Lysine
- Protein
- Amino Acid
- Nucleosome
- Methyllysine