Hiroki Abe

Simultaneous determination of d- and l-amino acids in the nervous tissues of crustaceans using precolumn derivatization with (+)-1-(9-fluorenyl)ethyl chloroformate and reversed-phase ion-pair high-performance liquid chromatography

After the derivatization of D- and L-amino acids with (+)-1-(9-fluorenyl)ethyl chloroformate, nineteen amino acids were separated into their D- and L-enantiomers and from other physiological amino compounds by reversed-phase ion-pair high-performance liquid chromatography. The separation was performed by three separate runs differing in mobile phase compositions and gradient profiles. Tyrosine, tryptophan and cysteine could not be detected because of their weak reactions with the derivatization reagent. Of seven D-amino acids found in the crustacean nervous tissues and eyes, D-alanine, D-arginine and D-aspartate were the most abundant and widely distributed.

Distribution of free l-histidine and related dipeptides in the muscle of fresh-water fishes

Abstract 1. 1. From the muscle of 20 species of fresh-water fishes, l -histidine, carnosine, anserine, and balenine were analysed by high-performance liquid chromatography. 2. 2. All cyprinoidei fishes contained significant amount of l -histidine and trace of dipeptides. 3. 3. High concentration of anserine was found in salmonoidei fishes, irrespective of salmonidae and osmeridae. 4. 4. Two species of anguilloidei contained large amount of carnosine, small of l -histidine, and determinable of anserine and balenine. 5. 5. Only trace amounts of these compounds were found in percoidei fishes. 6. 6. The levels of these compounds represented no large difference among species belonging to sub-order group as well as family.

Effects of carnosine and related compounds on generation of free oxygen species: a comparative study

The effect of carnosine and related compounds on the luminol- and lucigenin-dependent luminescence of rabbit leukocytes, activated by BaSO4, has been studied. Carnosine was found to modify BaSO4-induced chemiluminescence of leukocytes via suppression of hypochlorous anion generation with simultaneous stimulation the system of oxygen superoxide anion. Additionally to this effect carnosine prevents enzymic dismutation of O2.. Anserine, acetylanserine, and homocarnosine also possess the ability to activate O.2 production by leukocytes. The effect is not inherent to imidazole used in the same concentrations. Suppression of myeloperoxidase reaction by carnosine and related compounds is explained by both inhibiting action on the enzyme itself, and direct neutralization of hypochlorous anion due to formation of stable chloroamine complexes. Methylation of carnosine at N1 nitrogen of imidazole ring, leading to anserine, forced inhibition of myeloperoxidase system, whereas its acetylation at the free beta-amino group weakened this effect.

Chapter 14 Histidine-related dipeptides: distribution, metabolism, and physiological function

Publisher Summary This chapter describes the distribution, metabolism, and physiological function of histidine-related dipeptides. Animal tissue has long been known to contain quite a few different types of L-histidine-related dipeptides (imidazole dipeptides). The dipeptides refer to carnosine, anserine, balenine, and homocarnosine. Of these dipeptides, carnosine, anserine, and balenine may occur in the vertebrate skeletal muscle in large amounts depending on the species. Although the distribution of the dipeptides is restricted in the muscle of invertebrate and most white-fleshed fishes, such as percid and pleuronectid fishes, large amounts of these dipeptides are found in the wide variety of vertebrate muscles. Their distribution, however, lacks any phylogenetic basis. Balenine, for instance, which is found only in trace amount in most vertebrate muscles, is abundant in the muscle of snakes and whales. Camosine is rather common in vertebrate muscles, but some fishes and birds contain much higher amounts of anserine than camosine. The chapter discusses the distribution of free L-histidine and related dipeptides in fish tissues and elaborates the effects of physiological conditions on the dipeptide concentrations in the fish muscle.

Occurrence of Alanine Racemase in Crustaceans and the Changes of the Properties During Seawater Acclimation of Crayfish

Alanine racemase activity was detected in the muscle and hepatopancreas of six macruran species. Optimal pH was around 8.5 irrespective of species and tissues. Apparent Michaelis constants ranged from 48 to 157 mM for muscle enzyme and 35 to 239 mM for hepatopancreas enzyme. The enzyme specifically catalyzed the racemization of d- and l-alanine. The enzyme did not require pyridoxal 5′-phosphate as well as FAD as a cofactor. Pyruvate and l-alanine showed strong inhibition in the direction of d to l. n nDuring seawater acclimation of crayfish Procambarus clarkii, alanine racemase activity increased about twice in muscle and 1.5 times in hepatopancreas. Michaelis constant, on the other hand, decreased 33% for muscle enzyme and 65% for hepatopancreas enzyme, suggesting the increase of substrate affinity during seawater acclimation. The activity in the physiological pH range (6.5–7.5) also increased with increasing salinity.

Effect of carnosine and its Trolox-modified derivatives on life span of Drosophila melanogaster.

This study investigated the effect of antioxidants, i.e., carnosine and its Trolox- (water-soluble analog of alpha-tocopherol) acylated derivatives (S,S)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carbonyl-beta-alanyl-L-histidine (S,S-Trolox-carnosine, STC) and (R,S)-6-hydroxy-2,5,7,8-tetramethylchroman-2-carbonyl-beta-alanyl-L-histidine (R,S-Trolox-carnosine, RTC) on the life span of the fruit fly Drosophila melanogaster. Adding carnosine to foodstuff was accompanied and followed by a 20% increase in the average life span of males, but it did not influence the average life span of females. At the same time, adding STC to foodstuff prolonged average longevity both in males (by 16%) and females (by 36%), but the addition of RTC to foodstuff had no influence upon the average life span of insects of either gender. The compounds studied have previously been shown to protect neurons of the rat brain from oxidative stress in the descending order of efficiency: RTC > STC > carnosine. The finding obtained in the present study suggests another order of efficacy regarding the effect on life span in male insects: STC > carnosine > RTC (inefficient). No correlation between antioxidant protection of rat neurons and the effect on life span of the fruit fly makes it possible to suppose the presence of additional cellular targets to be acted upon by exposure of D. melanogaster to these compounds.

Analysis of novel imidazoles from isolated perfused rabbit heart by two high-performance liquid chromatographic methods

The paper reports two analytical high-performance liquid chromatographic methods to detect and quantify cardiac-derived histidyl derivatives. Method A relies on relative hydrophobicities as a basis of separation. Method B is an ion-pairing method in which the compounds are eluted in an entirely different order. Fractions collected from method A have been co-eluted in admixture in method B with authentic reference compounds. Thus the existence of the following imidazole ring-containing compounds derived from heart have been confirmed: N-acetylhistidine, N-acetyl-1-methylhistidine, N-acetylcarnosine, N-acetylhomocarnosine, homocarnosine, anserine, carnosine, balenine. Compounds were found in both tissue samples and perfusates.

Interorgan transport and catabolism of carnosine and anserine in rainbow trout.

1. After large amounts of carnosine or anserine were injected into rainbow trout white muscle, they were promptly washed out into blood and incorporated mainly into kidney. 2. These dipeptides were transported only a little to the other portions of white muscle but significantly to red muscle. 3. After anserine administration, pi-methyl-L-histidine, a constituent of anserine, increased largely in the kidney, followed by liver and muscles. 4. Histidine, a decomposed product of carnosine, increased in muscles after carnosine administration prior to the increase in kidney and liver.