New Agents for <i>t</i>-Butyloxycarbonylation and <i>p</i>-Methoxybenzyloxycarbonylation of Amino Acids

Nagasawa, Takeshi; Kuroiwa, Katsumasa; Narita, Kouichi; Isowa, Yoshikazu

doi:10.1246/bcsj.46.1269

Cited by 135 publications

(29 citation statements)

References 7 publications

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“…MATERIALS AND METHODS 13-Chloro-L-alanine was synthesized from L-serine (5); disodium diselenide was prepared by the method of Klayman and Griffin (6); L-selenocysteine was prepared from disodium diselenide and /-chloro-L-alanine (7); Se-(p-methylbenzyl)-L-selenocysteine was obtained from L-selenocysteine and a-bromo-p-xylene by a modification of the procedure of Erickson and Memfield (8); N-(tert-butyloxycarbonyl)-Se-(p-methylbenzyl)-L-selenocysteine was prepared from Se-(pmethylbenzyl)-L-selenocysteine and S-(tert-butyloxycarbonyl)-4,6-dimethyl-2-thiopyrimidine by a modification of the procedure of Nagasawa et al (9). Other reagents, the best grade commercially available, were used without further purification.…”

mentioning

confidence: 99%

Metalloselenonein, the selenium analogue of metallothionein: synthesis and characterization of its complex with copper ions.

Oikawa

Esaki

Tanaka

et al. 1991

Proc. Natl. Acad. Sci. U.S.A.

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We used an automated peptide synthesizer to produce a peptide, metalloselenonein, that contains selenocysteine residues substituted for all cysteine residues in Neurospora crassa copper metallothionein. Metalloselenonein binds 3 mol of Cu(I) per mol. This adduct shows a broad absorption band between 230 and 400 nm and a fluorescence band at 395 nm, which can be attributed to copper-selenolate coordination. The circular dichroism spectrum of the copper-metalloselenonein complex shows a positive band around 245 nm attributable to asymmetry in metal coordination.A selenocysteine residue occurs as an integral moiety in the active center of the selenium-containing enzymes such as glycine reductase, formate dehydrogenase, and glutathione peroxidase (1). The catalytic role of the selenocysteine residue is attributed to the high reactivity of the selenol group: selenols have much lower redox potentials than their sulfur counterparts (2). Thus, attention has been paid to synthesis of selenocysteine-containing polypeptides and proteins, which may have properties that the sulfur counterparts do not have (3).Metallothioneins are low molecular weight, cysteine-rich proteins that bind various kinds of metal ions (4). The biological functions of metallothioneins have been proposed to be involved in provision of physiological metals for metalloenzymes and in storage and detoxification of heavy metals. These functions depend on high affinity for metal ions and the reactivity of cysteine residues in a metal-thiolate cluster. Here we describe the synthesis ofmetalloselenonein, in which all the cysteine residues in the Neurospora crassa copper metallothionein are replaced by selenocysteines, and its interaction with copper ions.

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mentioning

confidence: 99%

Metalloselenonein, the selenium analogue of metallothionein: synthesis and characterization of its complex with copper ions.

Oikawa

Esaki

Tanaka

et al. 1991

Proc. Natl. Acad. Sci. U.S.A.

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“…10 For reprotection we used three different ready-to-use tert-butoxycarbonylating agents: 1,2,2,2-tetrachloroethyl tert-butyl carbonate, 18 di-tert-butyl dicarbonate, 19 and tert-butyl S-(4,6-dimethylpyrimidin-2-yl) thiolcarbonate (Boc-S). 20 Monitoring reactions represents one of the major drawbacks of solid-phase chemistry. 21 In order to examine the progress of the reaction, we first carried out the transprotection of FmocAla-OMe in solution.…”

Section: Resultsmentioning

confidence: 99%

Efficient and simple one-pot conversion of resin-bound N-Fmoc amino acids and dipeptides into N-Boc derivatives

Furlán¹,

Mata²

2003

Arkivoc

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“…16 • 17 Boc-X-Glu(OBzl)-Ala-LeuGly-OPac was obtained by the stepwise chain-elongation in previous studies. 6 The host-guest pentapeptides were prepared in a mixture of CH 2 Cl 2 and N,N-dimethylformamide (DMF) by coupling reactions of Boc-X-OH with HCl · H-Glu(OBzl)-Ala-Leu-Gly-OPac, which were obtained from the corresponding Boederivatives by treatment with 3.6 M (1 M = 1 mol dm - 3 ) HCI/ AcOEt as shown in Scheme 1.…”

Section: Methodsmentioning

confidence: 99%

Only Weak Dependence of the Protected Peptides Solubility in Organic Solvents on Their Amino Acid Sequence

Ou-uchi

Yang

Lee

et al. 1996

Polym J

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ABSTRACT:The adequacy of the hypothesis that the protected peptide solubility only weakly depended on their amino acid sequence was confirmed by the evaluation of the /J-sheet-structure stability of protected peptides. As the {J-sheet-structure stability of protected peptides is related with their solubility, it is investigated by the solvent-titration method using the protected host-guest peptides, Boc-(X-Glu(OBzl)-Ala-Leu-Gly)n-OPac (n= 1, 2) which have the same amino acid composition with Boc-(X-Ala-Glu(OBzl)-Leu-Gly).-OPac (n= I, 2) studied previously. In fact, the results show concurrently that the {J-sheet-structure stability of pentapeptides is useful for the estimation of protected peptide solubility in organic solvents and only weakly dependent on their amino acid sequence. It is also little weakly dependent on the solvation mechanism, by which peptides they solvate with an electron acceptor or donor solvent. The {J-sheet-structure stability of protected decapeptides is also strongly dependent on their amino acid composition and only weakly dependent on their amino acid sequence. The significance of the hypothesis for the prediction of the protected protein solubility is briefly discussed.

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New Agents for t-Butyloxycarbonylation and p-Methoxybenzyloxycarbonylation of Amino Acids

Cited by 135 publications

References 7 publications

Metalloselenonein, the selenium analogue of metallothionein: synthesis and characterization of its complex with copper ions.

Metalloselenonein, the selenium analogue of metallothionein: synthesis and characterization of its complex with copper ions.

Efficient and simple one-pot conversion of resin-bound N-Fmoc amino acids and dipeptides into N-Boc derivatives

Only Weak Dependence of the Protected Peptides Solubility in Organic Solvents on Their Amino Acid Sequence

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