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PubMed1982

Pipecolic acid: a new type of alpha-amino acid possessing bicuculline-sensitive action in the mammalian brain.

Using unit recording and electrophoretic techniques, pharmacological properties of pipecolic acid (PA) were studied in the brain neurons of rats. PA response was blocked by bicuculline more effectively than GABA response but not blocked by strychnine. Stereochemical findings obtained using the HGS-model demonstrated that PA structure is almost the same as a part of bicuculline structure. The present results suggest that PA might be a new type of substance possessing bicuculline-sensitive action. The site of the action of PA was also discussed.

Animals↗
PubMed1977

Immunological and biological characteristics of a new TRF analogue, L-pyroglutamyl-L-histidyl-L-pipecolic acid amide.

The immunological and biological potencies of a new synthetic TRF analogue, L-pyroglutamyl-L-histidyl-L-pipecolic acid amide, were compared with those of TRF. In a radioimmunoassay system for TRF, parallel inhibition curves were obtained with TRF and the analogue, the immunological potency of the latter being approximately 50 per cent of the former. In vitro and in vivo TSH-releasing activities of the analogue were almost equal to those of TRF. As was observed with TRF, the in vitro TSH-releasing effect of the analogue was reduced in the presence of T4, and the analogue was inactivated by incubation with rat serum. The data suggest that the pyrrolidine ring of TRF can be replaced with piperidine ring without significant loss of the biological activity.

Animals↗
PubMed2003

Central pipecolic acid increases food intake under ad libitum feeding conditions in the neonatal chick.

It has been demonstrated that L-pipecolic acid (L-PA) is a major metabolic intermediate of L-lysine in the mammalian and chicken brain. A previous study showed that intracerebroventricular (i.c.v.) injection of L-PA suppressed feeding in neonatal chicks, and the actions were associated with gamma-aminobutyric acid (GABA)-B receptor activation. It has been reported that endogenous L-PA in the brain fluctuated under different feeding conditions. In the present study, we investigated the effect of i.c.v. injection of L-PA on food intake in the neonatal chick under ad libitum feeding conditions. The food intake was increased by 0.5 or 1.0 mg L-PA under ad libitum feeding conditions contrary to previous studies using fasted birds. A hyperphagic effect of L-PA (0.5 mg) was attenuated by both GABA-A receptor antagonist (picrotoxin, 0.5 microg) and GABA-B receptor antagonist (CGP54626, 21.0 ng). These results indicate that a hyperphagic effect of L-PA is mediated by both GABA-A and GABA-B receptors and L-PA differentially affects food intake under different feeding conditions in the neonatal chick.

Animals↗
PubMed2001

Intracerebroventricular injection of pipecolic acid inhibits food intake and induces sleeping-like behaviors in the neonatal chick.

It has been demonstrated that L-pipecolic acid (L-PA), a major metabolic intermediate of L-Lysine (L-Lys) in the brain, is involved in the functioning of Gamma-aminobutyric acid. In the present work the effect of intracerebroventricular (i.c.v.) administration of L-PA, and its relatives, on food intake and behavior in neonatal chicks was investigated. The i.c.v. injection of 1 mg of L-PA and D-PA significantly inhibited food intake during the 2 h following injection, whereas greater than 2 mg of L-Lys was required to inhibit food intake. In behavioral tests, the i.c.v. injection of L-PA reduced active wakefulness and feeding behavior while inducing sleeping-like behavior in chicks. These results suggest that L-PA has an important role for the regulation of behaviors in the neonatal chick after conversion from L-Lys in the brain.

Age Factors↗
PubMed2002

Increase in the rate of L-pipecolic acid production using lat-expressing Escherichia coli by lysP and yeiE amplification.

Biotransformation of L-lysine (L-Lys) to L-pipecolic acid (L-PA) using lat-expressing Escherichia coli has been reported (Fujii et al., Biosci. Biotechnol. Biochem., 66, 622-627 (2002)). The rate-limiting step of this biotransformation seemes to be the transport of L-Lys into cells. To improve the L-PA production rate, we attempted to increase the rate of L-Lys uptake. E. coli BL21 carrying a plasmid with lat and lysP (pRH125) caused a 5-fold increase in the rate of L-PA production above the level of cells carrying a plasmid with lat (pRH124). Moreover, E. coli BL21 carrying a plasmid with lat, lysP, and yeiE (pRH127) caused a 6.4-fold increase in the rate of L-PA production above the level of cells carrying pRH124. Our results from RT-PCR experiments and the sequence similarity of YeiE to LysR transcriptional regulators suggest the possibility that yeiE expression induces lysP expression. The amplification of lysP, or rather both lysP and yeiE, increases the rate of L-PA production using lat-expressing E. coli.

Amino Acid Transport Systems, Basic↗
PubMed1994

Pipecolic acid is an osmoprotectant for Escherichia coli taken up by the general osmoporters ProU and ProP.

Exogenously supplied L-pipecolic acid was accumulated by Escherichia coli cells and protected them while growing at inhibitory osmolarity. Using specific uptake mutants and competitive assays, we established that the imino acid enters the cells through the ProP and ProU systems with Km values of 225 and 53 microM, respectively. Surprisingly, in spite of the requirement for the wild-type proX gene for osmoprotective ability, no binding activity of labelled pipecolate with the periplasmic protein encoded by proX could be detected. In an attempt to demonstrate whether the two porters (ProP and ProU) are the only carriers involved in osmoregulation, a variety of molecules known for their intracellular osmolarity-dependent accumulation in various organisms were investigated. N-Dimethylproline (proline betaine), N-dimethylglycine, homobetaine (beta-alanine betaine), gamma-butyrobetaine and dimethylsulfoniopropionate were found to be capable of promoting the growth of osmotically stressed E. coli. All of these molecules enter bacterial cells via ProP and ProU porters. None of the osmoprotectants except N-dimethylproline was able to bind the periplasmic protein encoded by proX, while this protein was necessary for their uptake. Apparently, ProP and ProU are the sole osmoporters involved in osmolyte influx into E. coli cells.

Amino Acid Transport Systems↗
PubMed1999

Simple method for the simultaneous analysis of pipecolic acid and lysine by high-performance liquid chromatography and its application to rumen liquor and plasma of ruminants.

A high-performance liquid chromatography method for the simultaneous determination of pipecolic acid (Pip) and lysine (Lys), a precursor of Pip, in the rumen liquor and plasma of ruminant animals was established. Samples of rumen liquor and plasma were deproteinized with 50% acetonitrile and derivatized with a fluorescent agent 9-fluorenylmethyloxy carbonyl chloride (Fmoc-Cl). Chromatographic separation was achieved on a TSK gel ODS-80TM column using a reversed-phase gradient elution system. For the gradient elution, two mobile phases, A and B, were needed, both commonly consisted of: 5 mM L-proline, 2.5 mM cupric sulfate and 6.5 mM ammonium acetate. Mobile phase B additionally contains 50% (v/v) acetonitrile. The pH of both mobile phases was adjusted to 7.0. Derivatized Pip and Lys were detected on a fluorescent detector at excitation and emission wavelengths of 260 and 313 nm, respectively. The calibration curves were linear within the range 0 to 1 mM (r>0.999). The average recoveries for Pip and Lys were 95.9+/-1.8 and 93.2+/-2.5% in rumen liquor and 98.3+/-1.4 and 97.5+/-1.3% in plasma, respectively. The limits of detection for Pip and Lys were 0.6 and 0.7 microM in rumen liquor and 0.01 and 0.05 microM in plasma. The assay has acceptable precision, relative standard deviation (RSD) for reproducibility (within-day and day-to-day variation) were less than 5.2% for aqueous (5.0 microM Pip and Lys), MB9 (5.0 microM Pip and Lys), plasma (7.1 microM Pip and 85.6 microM Lys) and rumen liquor (28.4 microM Pip and 10.2 microM Lys) samples. The levels of Pip and Lys in faunated goats, determined from three animals over a period of two days sampling, were found to be 36.8+/-18.1 and 14.6+/-2.8 microM in rumen liquor, and 7.3+/-2.5 and 137.3+/-38.0 microM in plasma at 1 h after feeding. This is the first report on the normal levels of Pip in the rumen liquor and plasma of faunated goat.

Animals↗
PubMed1975

Cerebro-hepato-renal syndrome of Zellweger. A report of eight cases with comments upon the incidence, the liver lesion, and a fault in pipecolic acid metabolism.

Studies of eight patients with this syndrome confirm the characteristic pattern of abnormalities and the autosomal recessive mode of inheritance. The incidence is estimated to be approximately 1 in 100,000 live births. The liver lesion proved to be variable, with features of progressive parenchymal damage rather than a developmental defect of small bile ducts as previously suggested. Elevated levels of pipecolic acid were found in blood and urine and may be related to the basic defect.

Acidosis↗
PubMed1990

Substitution of proline with pipecolic acid at the scissile bond converts a peptide substrate of HIV proteinase into a selective inhibitor.

The nonapeptide H-Val-Ser-Gln-Asn-Tyr-Pro-Ile-Val-Gln-NH2 containing the retroviral Tyr-Pro cleavage site is a good substrate for the proteinase of human immunodeficiency viruses but it is not readily hydrolyzed by other nonviral proteinases including the structurally related pepsin-like aspartic proteinases. Replacing the Pro by L-pipecolic acid (2-piperidinecarboxylic acid) converted the substrate into an effective inhibitor of HIV-1 and HIV-2 proteinases with IC50 of approximately 1 microM. This compound showed a high degree of selectivity in that it did not inhibit cathepsin D and renin.

Amino Acid Sequence↗
PubMed1995

NMDA receptor heterogeneity in mammalian tissues: focus on two agonists, (2S,3R,4S) cyclopropylglutamate and the sulfate ester of 4-hydroxy-(S)-pipecolic acid.

Several potent and selective agonists of the glutamate (L-GLU) receptors of N-methyl-D-aspartate (NMDA) type have been tested on the L-[3H]GLU binding to rat cortical membranes, on the depolarization of mouse cortical wedges and on the contraction of guinea pig longitudinal muscle myenteric plexus preparations with the aim of comparing the NMDA receptors present in the cortex and those present in the gut. When the depolarization of the cortical wedges was evaluated, the EC50 values of the agonists were (microM): (R,S)-(tetrazol-5-yl)-glycine (TG) 0.3; trans-4-hydroxy-(S)-pipecolic acid-4-sulfate (t-HPIS) 0.7; 1-aminocyclobutane-cis-1,3-dicarboxylic acid (ACBD) 0.8; NMDA 8; (2S,3R,4S) cyclopropylglutamate (L-CGA C) 12; quinolinic acid (QUIN) 400. When the contraction of the longitudinal muscle myenteric plexus was evaluated, the EC50 values were (microM): L-CGA C 1; TG 8; ACBD 50; t-HPIS 100; QUIN 500 and NMDA 680. When the displacement of NMDA specific L-[3H]GLU binding from rat cortical membranes was evaluated, the IC50 values were (microM): L-CGA C 0.003; TG 0.005; ACBD 0.044; t-HPIS 0.062; NMDA 0.31 and QUIN 15. No significant correlation was found when the EC50 values obtained in the ileum were plotted against the EC50 values obtained in the cortex (r = 0.47). In particular it was noted that L-CGA C was approximately three orders of magnitude more potent than NMDA when tested in the ileum but had a potency not significantly different from that of NMDA when tested in the cortex.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids, Dicarboxylic↗
PubMed1982

In vitro activity of pipecolic acid amide of clindamycin (U-57930E) on anaerobic bacteria compared with those of clindamycin, cefoxitin, and chloramphenicol.

In vitro activity of pipecolic acid amide of clindamycin (U-57930E) against 265 isolates of anaerobic bacteria, including 66 strains of Bacteroides fragilis, was compared with those of clindamycin, chloramphenicol, and cefoxitin. At therapeutically achievable concentrations, the activities of all four antibiotics against anaerobic bacteria were similar.

Bacteria, Anaerobic↗
PubMed1966

Metabolism of Pipecolic Acid in a Pseudomonas Species IV. Electron Transport Particle of Pseudomonas putida.

Baginsky, Marietta L. (University of California, San Francisco Medical Center, San Francisco), and Victor W. Rodwell. Metabolism of pipecolic acid in a Pseudomonas species. IV. Electron transport particle of Pseudomonas putida. J. Bacteriol. 92:424-432. 1966.-Enzymes of Pseudomonas putida P2 catalyzing oxidation of pipecolate to Delta(1)-piperideine-6-carboxylate are located in a subcellular fraction sedimenting at 105,000 x g. Since this fraction resembles the mammalian electron transport particle in both chemical composition and enzymatic activities, it was termed Pseudomonas P2 electron transport particle (P2-ETP). P2-ETP contains flavin adenine dinucleotide, flavin mononucleotide, iron, copper, and both b- and c-type cytochromes. The reduced type b cytochrome has absorption maxima at 558 to 559, 530, and 427 mmu. Its oxidized pyridine hemochromogen has an absorption maximum at 406 mmu, with a shoulder at 564 mmu. On dithionite reduction, absorption bands with maxima at 556, 522, and 418 mmu are obtained. The reduced type c cytochrome has absorption maxima at 552, 520, and 422 mmu; its reduced pyridine hemochromogen has maxima at 551, 516 to 519, and 418 mmu. No type a cytochrome was detected. P2-ETP catalyzes oxidation of pipecolate and of reduced nicotinamide adenine dinucleotide (NADH(2)) by oxygen. It can also oxidize these compounds, as well as succinate and reduced nicotinamide adenine dinucleotide phosphate, with 2,6-dichlorophenol-indophenol as electron acceptor. Mammalian cytochrome c can be used as an alternate artificial electron acceptor for the oxidation of pipecolate and succinate, but not for oxidation of NADH(2).

Journal Article↗