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Amino Acids: The Forum for Amino Acid, Peptide and Protein Research (v.14, #4)

A review of physiological and metabolic effects of essential amino acids by K. A. Massey; C. H. Blakeslee; Dr. H. S. Pitkow (pp. 271-300).

The authors review ten essential amino acids with regard to their metabolic, physiologic and therapeutic effects throughout the human body. Physical properties of these biologically active compounds are discussed as a foundation for their diverse roles in special nitrogen containing products, neurotransmitters, and as alternative energy sources. Both normal and abnormal amino acid metabolism are considered in the areas of digestion, elimination of metabolic products, metabolic intermediates, and defects in these systems. Recent developments in therapeutic applications are further examined for clinical utility and as an economical alternative to traditional clinical treatment modalities.

Keywords: Essential amino acids; Therapeutic applications; Physiological effects; Metabolism

Modified chemotactic peptides: Synthesis and activity of an azaTic-containing fMLP-OMe analogue by G. Pagani Zecchini; I. Torriai; M. Paghalunga Paradisi; Prof. G. Lucente; G. Mastropietro; S. Spisani (pp. 301-309).

The synthesis and the biological activity of a pseudopeptide analogue of the chemotacticN-formyltripeptide fMLP-OMe, containing the aza Tic (3,4-dihydro-2(1H)-phthalazinecarboxylic acid) residue replacing the native phenylalanine, is described. Whereas pseudopeptides containing lineara-azaammo acids are currently studied, data on the new group of analogues containing cyclicα-aza residues capable of limiting the rotameric distribution of the side chains (topological control) are just emerging in the literature. At our best knowledge, the here described [azaTic³]fMLP-OMe represents the first example of the introduction of this new type ofα-aza residue into a natural bioactive peptide.

Keywords: Amino acids; Azapeptides; AzaTic; Chemotaxis; 3,4Dihydro-2(1H)-phthalazinecarboxylic acid; Formylpeptides

Asymmetric imine-ene reactions: Diastereofacial selective reactions with chiral glyoxylate-derivedα-imino esters and asymmetric catalysis of enantiofacial selective reactions with prochiralα-imino esters by Dr. K. Mikami; T. Yajima; M. Kaneko (pp. 311-318).

The diastereofacial selective “imine-ene” reactions withα-imino esters, prepared from (−)-8-phenylmenthyl glyoxylate, are shown to provide an efficient entry to the asymmetric synthesis ofα-amino acids. The feasibility study of the asymmetric catalysis is also reported on the enantiofacial selective ene reactions with prochiralα-imino esters.

Keywords: Amino acids; Ene reaction; Diastereofacial selectivity; Enantiofacial selectivity; Binaphthol titanium complex

Microdialysis of excitatory amino acids in the periaqueductal gray of the rat after unilateral peripheral inflammation by Dr. W. M. Renno (pp. 319-331).

This study measured the release of glutamate (Glu) and aspartate (Asp) amino acid transmitters in the ventrocaudal compartment of the rat periaqueductal gray (PAG) following exposure to unilateral peripheral inflammation. The release of endogenous Glu and Asp from the rat ventrocaudal PAG was monitored with the microdialysis technique in unanesthetized, unrestrained rats. There was significant increase (1,300%) in the basal concentrations of Glu release in the 7 days Complete Freund's Adjuvant (CFA) treated group compared to 24h mineral oil control group. Amino acid release was induced by infusing veratridine (75μM, a sodium channel activator) directly through the 1 mm long dialysis probe. Perfusion of veratridine into the ventrocaudal PAG resulted in significant elevation of Glu and Asp amino acids. In the 24h and 7 days CFA treated rats, veratridine-evoked release of Glu was significantly decreased in the lateral ventrocaudal PAG compared to control rats injected with mineral oil (CFA vehicle). The peak minus baseline concentrations of Glu in 24h and 7 days CFA treated groups decreased 55.7% and 43.9%, respectively. In contrast, The basal and the peak minus baseline concentrations of Asp showed no significant change between control group and 24h and 7 days CFA treated animals. The results provide direct evidence that Glu excitatory amino acid may be involved in nociception/nociception modulation pathway in the ventrocaudal PAG.

Keywords: Amino acids; Analgesia; Aspartate; Glutamate; Nociception; Pain

Design and synthesis of small semi-mimetic peptides with immunomodulatory activity based on Myelin Basic Protein (MBP) by T. Tselios; L. Probert; G. Kollias; E. Matsoukas; P. Roumelioti; K. Alexopoulos; G. J. Moore; J. Matsoukas (pp. 333-341).

Experimental allergic encephalomyelitis (EAE) is induced in susceptible animals by immunodominant determinants of myelin basic protein (MBP). Analogs of these disease-associated peptides have been identified with disease progression upon coimmunization. Usage of peptides, with disease-specific immunomodulatory capacity in vivo is limited, however, due to their sensitivity to proteolytic enzymes. Alternative approaches include the development of mimetic molecules which maintain the biological function of an original peptide, yet are stable and able to elicit their response in pharmacological quantities. A novel technique was employed to design a series of semi-mimetic peptides, based on the guinea pig MBP_72–85 peptide used to induce EAE in Lewis rats. We used isonipecotic (iNip) and aminocaproic (Acp) acids as templates. Acp-MBP_72–85 peptide derived analogues were effective in inducing EAE compared to iNip-peptide analogues which were ineffective at 350μg. These findings suggest that the design and synthesis of semi-mimetic peptide molecules with immunomodulatory potential is possible and that eventually these molecules may form the basis for the development of novel and more effective disease-specific therapeutic agents.

Keywords: Amino acids; Experimental allergic encephalomyelitis (EAE); Myelin basic protein (MBP); Semi-mimetic peptides

Analysis of HIV by entropy evolution rate by Dr. K. Sato; S. Miyazaki; Prof. Dr. M. Ohya (pp. 343-352).

We analyze the variation of HIV after infection by means of an information measure, called the entropy evolution rate. In our analysis, we use a part of the external glycoprotein gp120 including the V3 region observed from six patients.the relation between the change of the entropy evolution rate and the appearance of symptoms of disease, andthe relation between the change of the entropy evolution rate and that of the CD4 count of the patients.

Keywords: Amino acids; HIV; Entropy evolution rate

Occurrence of freed-aspartate and aspartate racemase in the blood shellScapharca broughtonii by T. Watanabe; K. Shibata; Y. Kera; Dr. Ryo-Hei Yamada (pp. 353-360).

Substantial concentrations of D-aspartate were found in several tissues of Scapharca broughtonii together with approximately equal concentrations ofl-aspartate. The foot and mantle extracts also contained an aspartate racemase activity. The formation ofl-aspartate from the Denantiomer by the foot extract was apparently slower than the reverse reaction, and this unbalance seemed to be due to the presence of an enzyme activity which rapidly convertedl-aspartate tol-alanine. The possible role of D-aspartate in the anaerobiosis was discussed.

Keywords: Amino acids; D-Aspartate; Aspartate racemase; l-Alanine; Scapharca broughtonii ; Bivalve

Free carnitine and acetyl carnitine plasma levels and their relationship with body muscular mass in athletes by R. Gatti; C. B. De Palo; P. Spinella; Prof. E. F. De Palo (pp. 361-369).

The purpose of the present study was to investigate the relationship between plasma carnitine concentration and body composition variation in relation to muscular and fat masses since there is no experimentally proved correlation between plasma carnitine and body masses. We used bioelectric impedance analysis (BIA), to determine body composition and to have a complete physical fitness evaluation. The post-absorptive plasma free carnitine and acetyl carnitine plasma levels, body composition as Fat-Free Mass (FFM) and Fat Mass (FM) in kg, as well as in percent of body mass, were analysed in 33 healthy subjects. A significant negative correlation was found between plasma acetyl carnitine and FFM in weight (kg) as well as in percent of body mass (respectively p < 0.0001; p < 0.01); a significant positive correlation was found only between FM in percent and plasma acetyl carnitine (p < 0.01). The observed negative correlation between plasma acetyl carnitine and muscular mass variation might reflect an oxidative metabolic muscle improvement in relation to muscular fat free mass increment and might be evidence that muscle metabolism change is in relation to plasma acetyl carnitine concentration.

Keywords: Amino acids; Carnitine; Acetyl carnitine; Body composition; Bioelectric impedance; Muscular mass

Renal excretion ofγ-carboxyglutamic acid and metabolic rate in 3–18 years old humans by Dr. H. Topp; V. Iontcheva; G. Schöch (pp. 371-377).

The modified amino acid y-carboxyglutamic acid (Gla) occurs in several proteins such as prothrombin, blood coagulation factors VII, IX and X, proteins C, S and Z as well as matrix Gla protein and osteocalcin. The amount of Gla excreted in urine is a common indicator of the whole-body degradation of these proteins. We have determined the renal excretion rates of Gla in 3, 6,10,14 and 18 years old male and female human subjects (n = 14 per age group and sex) and calculated the respective resting metabolic rates (RMR) on the basis of the body weights using published formulas. We found high correlations between the excretion rates of Gla (µmol/d/kg body weight) and the RMR (kJ/d/kg body weight) in the females (n = 70) of r = 0.70 (y = 0.003x + 0.29) and in the males (n = 70) of r = 0.70 (y = 0.0038x + 0.27) and in all subjects (n = 140) of r = 0.69 (y = 0.0035x + 0.27); p < 0.01. We postulate that in children and adolescents a causal relationship exists between the whole-body degradation rate of Gla containing proteins and the metabolic rate.

Keywords: Amino acids; γ-Carboxyglutamic acid; Metabolic rate; Urinary protein catabolites; Reactive oxygen species

System b^0,+-mediated regulation of lysine transport in Caco-2 human intestinal cells by H. Satsu; H. Watanabe; S. Arai; Dr. M. Shimizu (pp. 379-384).

We investigated whether lysine transport would be subject to adaptive regulation in Caco-2 human intestinal cells. The activity of Lys transport in Caco-2 cells decreased with increasing incubation time with lOmM Lys. Among the two systems involved in Lys transport, the system b^0,+ component was greatly decreased by incubating cells ith lOmM Lys, whereas the system y⁺ component did not change. These results suggest that system b^0,+ mainly contributes to the adaptive regulation of Lys transport in Caco-2 cells.

Keywords: Amino acids; Lysine; Transporter; Caco-2; Adaptive regulation

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Amino Acids: The Forum for Amino Acid, Peptide and Protein Research (v.14, #4)

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Amino Acids: The Forum for Amino Acid, Peptide and Protein Research (v.14, #4)