Amino Acid Analogues

Shive, William; Skinner, Charles G.

doi:10.1016/b978-0-12-395622-4.50006-9

Cited by 24 publications

(34 citation statements)

References 470 publications

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“…Radioactive metabolites in amounts indicated with the tables in the Results section were added to the buffer solutions. In some experiments the influence of azaserine (O-diazoacetvl-L-serine), an inhibitor of reactions involving glutamine (9,17), was studied. It was added to the above-mentioned componenits in the main conmpartments of the flasks just prior to adding the leaf discs.…”

Section: Methodsmentioning

confidence: 99%

Metabolism of Cytidine and Uridine in Bean Leaves

Ross

Callebaut²

1968

Plant Physiol.

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Abstract. The metabolism of cytidine-2-14C and uridine-2-14C was studied in discs cut from leaflets of bean plants (Phaseolus vulgaris L.). Cytidine was degraded to carbon dioxide and incorporated into RNA at about the same rates as was uridine. Both nucleosides were converted into the same soluble nucleotides, principally uridine diphosphate glucose, suggesting that cytidine was rapidly deaminated to uridine and then metabolized along the same pathways. However, cytidine was converted to cytidine diphosphate and cytidine triphosphate more effectively than was uridine. Cytidine also was converted into cytidylic acid of RNA much more extensively and into RNA uridylic acid less extensively than was uridine. Azaserine, an antagonist of r.actions involving glutamine (including the conversion of uridine triphosphate to cytidine triphosphate), inhibited the conversion of cytidine into RNA uridylic acid with less effect on its inoorporation into cytidylic acid. On the other hand, it inhibited the conversion of orotic acid into RNA cytidylic acid much more than into uridylic acid. The results suggest that cytidine is in part metabolized by direct conversion to uridine and in part by conversion to cytidine triphosphate through reactions not involving uridine nueleotides.Nucleosides stuch as cvtidinie are known not to be intermediates in the usual fornmation of pyrimidine nucleotides (4, 5, 15, 16, 19). Nevertheless, these compounds may be important in mlechanisms salvaging the purine and pvrimidille rings. Ribonuclease action upon RNA apparently produces 5'-nucleotides (22) or 2',3'-cyclic niucleotides (3,22 We previously showed that uridine is a nmuclh better precursor of RNA in trifoliate bean leaves (16) than is uracil, and Wasilewska and Reifer (21) made the same observation in experiments wvith wheat, pea, and spinach leaves. WNe further found that cytosine was not metabolized in either bea:n or cocklebur leaves. These facts indicate that pvrimidine nucleosides are more important salvage produticts than are free pyrimidines. The mechanisnm of utilization of uridine has been given some attention (16,20,21), and although cvtidine can be converted into RNA of plants (2), the reactions involved have not been studied. The present experimnents were undertaken to determine whether cvtidine can be readily utilized in RNA syintlhesis and to determine some of the internmediates in the pathwvay concerned. Materials and MethodsLeaflets fronm Idaho 111 pinto beani (Pliascolts zllzgaris L.) plants were used in these studies, since we already had information about pyrimidine nucleotide metabolism in them (16,23). The plants were grown in soil-containing pots in a greenhouse unltil the first trifoliate leaflets were about 2. cmil long. Discs (1.2 cm diameter) were cut with a cork borer from these leaflets, rinsed in water, and 10 (225 mg fr wt) placed in flasks (2-oz. Skrip ink bottles) containing 5.0 ml of 0.02 Mi phosphate buffer at pH 5.8. Radioactive metabolites in amounts indicated with the tables in the Results section were ...

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Section: Methodsmentioning

confidence: 99%

Metabolism of Cytidine and Uridine in Bean Leaves

Ross

Callebaut²

1968

Plant Physiol.

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“…First, amino acid analogs are known to act as false endproduct inhibitors or as false repressors for enzymes involved in the biosynthesis of amino acids (15,27). If analogs shift the phase by disturbing the biosynthesis of amino acids, some consistency is expected between the native of the standard amino acid from which analogs are derived and the phase shifting.…”

Section: Discussionmentioning

confidence: 99%

“…2B), 5 AM AZD (19) and 60 pM DPR (27). AZD caused large phase delays with a breakpoint at CT 9, while DPR caused both large delays and advances with a breakpoint at the same time as that with DPR (CT 9).…”

Section: Analogs Of Prolinementioning

confidence: 98%

“…3A). CSE is an analog formed by making a ring structure that includes the a carbon of the amino acid and has been reported to compete with ,B-alanine (27). CSE has, thereby, lost the common structure of the standard a-amino acids.…”

Section: Analogs Of Alaninementioning

confidence: 99%

“…If an analog shifts the phase by being incorporated into 'clock protein,' the time at which this analog shifts the phase should be linked to the time at which such a protein is synthesized. Moreover (27) or reference cited to each analog.…”

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confidence: 99%

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Comparison of Phase Shifts of the Circadian Rhythm of K⁺ Uptake in Lemna gibba G3 by Various Amino Acid Analogs

Kondo¹

1989

Plant Physiol.

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Phase shifts of the circadian rhythm of K+ uptake by Lemna gibba G3, caused by pulse administration of various amino acids analogs, were examined and compared. The various phase shifts were not due to any disturbance in the biosynthesis of amino acids, since the effective time of day and direction of the phase shift caused by analogs were not correlated with the standard amino acid which was modified. Effective analogs could be classified into three groups. The first group was effective during the middle subjective day and caused both advances and delays in phase. The second group was effective early in the subjective night, causing large delays and small phase advance. Analogs in the third group shifted the phase as did cycloheximide and were effective at the subjective dawn. Since the analogs of the third group were known to inhibit protein synthesis, it is likely that they shift the phase by lowering the level of some protein(s) important for the clock. By contrast, since the analogs in groups 1 and 2 are known to generate abnormal proteins, the different phaseshifting pattems caused by analogs in groups I and 2 suggest that at least two other proteins are important for the circadian timing loop. The amino acid analogs shift the phase as a result of their incorporation into these proteins instead of the standard amino acid. This probably alters the structure and/or activities of these proteins.Circadian rhythms are known to be the basic system that controls the adaptation of eukaryotic cells to the day-night alternating environment. However, little is known about the molecular mechanism of the underlying oscillator (master clock). Investigations ofphase shifting by pulse administration of specific drugs should be useful for elucidating the biochemical reaction(s) that may be involved in the clock mechanism (7). Examples of such drugs are inhibitors of cytoplasmic protein synthesis, which shift the phase of the circadian clock ofvarious organisms including Neurospora (3, 16), Gonyaulax (18, 34), Aplysia (36), and mammals (31). On the other hand, I reported that pulses of the leucine analog, FLE,' perturbed

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Differential inhibition of epstein‐barr virus induction by the amino acid analogue, L‐canavanine

Yamamoto

Mueller‐Lantzsch

Hausen

1980

Intl Journal of Cancer

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The effect of an amino acid analogue, L-canavanine, on the synthesis of Epstein-Barr virus (EBV) antigens was investigated in lymphoblastoid cells. The analysis revealed that after infection of BJAB and NC-37 cells with P3HR-I EBV synthesis of early antigen (EA) was not affected by canavanine in concentrations up to 8.4 mM. The synthesis of EBV-determined nuclear antigen (EBNA) and of viral capsid antigen (VCA) was significantly inhibited at concentrations higher than 2.8 mM. Spontaneous induction of EA in P3HR-I cells was not affected by canavanine. On the other hand, EA induction by the tumor promoter TPA resulted in some viral antigen induction depending on the time period of TPA exposure. Pretreatment of the cells overnight with canavanine followed by washing and addition of the tumor promoter did not suppress EA induction by TPA. These data support the concept that EA induction by superinfection follows a different pathway from antigen induction by chemical inducers.

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Amino Acid Analogues

Cited by 24 publications

References 470 publications

Metabolism of Cytidine and Uridine in Bean Leaves

Metabolism of Cytidine and Uridine in Bean Leaves

Comparison of Phase Shifts of the Circadian Rhythm of K⁺ Uptake in Lemna gibba G3 by Various Amino Acid Analogs

Differential inhibition of epstein‐barr virus induction by the amino acid analogue, L‐canavanine

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Amino Acid Analogues

Cited by 24 publications

References 470 publications

Metabolism of Cytidine and Uridine in Bean Leaves

Metabolism of Cytidine and Uridine in Bean Leaves

Comparison of Phase Shifts of the Circadian Rhythm of K+ Uptake in Lemna gibba G3 by Various Amino Acid Analogs

Differential inhibition of epstein‐barr virus induction by the amino acid analogue, L‐canavanine

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Comparison of Phase Shifts of the Circadian Rhythm of K⁺ Uptake in Lemna gibba G3 by Various Amino Acid Analogs