摘要:

An efficient synthesis of methionine enkephalin using a phenolic resin support is described. Analogues modified at their C‐termini, such as peptide acids, amides, methyl esters and compounds formed by their reduction, were prepared conveniently from common peptide phenyl ester resins. The resin was used in the synthesis of complex isosterically modified analogues designed to investigate the role the peptide backbone plays in receptor interaction. Free hexapeptide phenyl ester resins underwent intramolecular aminolysis liberating the corresponding cyclic peptide

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01923.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The trypsin and chymotrypsin inhibitor from chick peas (CI) is stable in HCl 0.001m– 0.01mand in KOH 0.01m– 0.05meven after 24 h. Increased KOH concentrations decrease considerably the inhibitory activity already after 1 h. Maleylation and succinylation of the inhibitor resulted in almost full loss of its trypsin‐inhibitory activity but had no effect on the chymotrypsin‐inhibitory activity. A series of modifications directed towards tyrosyl residues showed that iodination influenced only the chymotrypsin‐inhibitory activity; however, nitration and arsanilation affected not only the chymotrypsin‐inhibitory activity but also the trypsin‐inhibitory activity. Treatment of the inhibitor with CNBr and chloramine T resulted only in a decrease in the chymotrypsin‐inhibitory activity indicating that the only methionine is involved in the chymotrypsin‐inhibitory activity. When CI‐fragment A, previously treated with trypsin at pH 3.75, was further treated with carboxypeptidase B, a release of three lysyl residues per mole protein was found. CI was separated by equilibrium chromatography on SP‐Sephadex column into two isoinhibitors, CIIand CIII, respectively. Both inhibited trypsin and chymotrypsin with the same specific activity as CI. They differed from each other only in a glutamyl, aspartyl, glyc

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01924.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Boc‐Trp‐Leu hydrazide has been found to significantly inhibit growth of the L‐1210 and P388 murine lymphocytic leukemias. A series of related tryptophan dipeptides were prepared and found to be devoid of such activity. The tryptophan dipeptides were most conveniently obtained employing the DCCI‐NHS peptide bond‐forming

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01925.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The reagent 2‐carboxy‐4,6‐dinitrochlorobenzene (CDNCB) reacts with the imino, amino and sulfhydryl groups of model compounds. At pH 8.2, sulfhydryl groups react much faster than do amines. Nα‐Acetylhistidine, Nα‐acetyltyrosine and Nα‐acetyltryptophan do not react. Poly (l‐Lysine) and poly (dl‐lysine) react about 50 times as fast as does Nα‐acetyllysine. A dichloroanalog, 6‐carboxy‐2,4‐dinitro‐1,3‐dichlorobenzene, shows stepwise reactivity with amines. With bovine pancreatic ribonuclease, which contains no sulfhydryl, CDNCB reacts preferentially with thee‐amino of Lys‐41 at 450 times the rate with thee‐amino of Nα‐acetyllysine. The preferential reactivity at Lys‐41 is discussed in relation to the pK of Lys‐41, the cationic character of the active site cleft, and

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01926.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

Both dehydration and adrenalectomy of rats caused a significant reduction of immunoreactive β‐endorphin in the pituitary gland. β‐Endorphin in hypothalamus, however, was not altered in either dehydrated or adrenalectomized

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01927.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

This report describes the synthesis of 23 analogs of thyrotrophin releasing hormone,l‐pyroglutamic acid‐l‐histidyl‐l‐prolineamide, where only the pyroglutamic acid moiety is modified. Twelve of the analogs contain different heterocyclic rings or are derivatized pyrrolidone rings. The syntheses of these pyroglutamic acid analogs are also described. Peptide bond formation was generally achieved by catalyzing carbodiimide coupling with 1‐hydroxybenzotriazole. The histidine side chain was protected with the 2,4‐dinitrophenyl group during di‐ and tripeptide synthesis and was removed with benzenethiol. Final purification of tripeptides involved passage of synthetic material over a Dowex 1 – X4 (bicarbonate) column. The route for synthesis of thyrotrophin releasing hormone and its analogs is highly efficient, since the native hormone may be obtained wi

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01928.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

The use of sodium selenite as a catalyst in the presence of oxygen was a suitable technique to obtain in good yield an interchain S‐S dimeric form of horse muscle acylphosphatase. The dimer so obtained possesses kinetic properties very similar to those of the native enzyme. On the other hand the dimer has shown a generally lower stability in respect of the thermal inactivation, particularly in the acidic environment, to the lyophilization and to the proteolytic attack. As regards the 8murea inactivation, the dimer is not able to completely regain its activity by dilution, showing a behaviour quite different from that of the native enzym

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01929.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

N‐p‐Methoxybenzyloxycarbonyl andN‐tert.‐butyloxycarbonyl amino acid amides related to a series of natural amino acids were dehydrated to the corresponding Meoz‐ and Boc‐α‐aminonitriles. Deprotection of the latter derivatives afforded α‐aminonitriles related to alanine, tyrosine, phenylalanine, dihydrophenylalanine, histidine, Dopa, ornithine, asparagine and glutamine. Thioamidation with H2S/NH3or H2S/NEt3in general converted the protected amino nitriles to Meoz‐ and Boc‐α‐aminothioamides. When deprotected these furnished the α‐aminothioamides corresponding to alanine, tyrosine, phenylalanine, dihydrophenylalanine and histidine. For dehydration and thioamidation of histidine and Dopa, Nα‐Boc‐imtrityl‐histidine and N‐Boc‐0, 0′‐diacetyldihydroxyphenylalanine were useful. Dopa was obtained as the free and Boc‐thiohydrazide. Also prepared wereNα,ω ‐diMeoz‐ornithine DCHA, Meoz‐2,5‐dihydrophenylalanine DCHA andN,0‐diMeoz‐tyrosine as starting materials andN,0‐dicarbobenzyloxycarbonyltyrosinamide, N,0‐diZ‐tyrosine nitrile and Z‐β‐cyano‐β‐alaninamide as model compounds. During deprotection of Meoz‐alanine thioamide, transfer of an anisyl group from theN‐Meoz protecting group to sulfur took place as a side reaction that yielded alaninep‐methoxybenzyl β‐imidothiolic ester. This study provides two new series of amino acid analogs with potential antimetabolite activity. Also suitable for incorporation into peptide analogs, these afford approaches

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01930.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

[7‐(Azetidine‐2‐carboxylic acid)]‐oxytocin and ‐lysine‐vasopressin have been synthesised by a (6 + 3) strategy using protected hexapeptide acids with preformed disulphide bridges, and their biological activities have been investigated. All activities were reduced but not to the same extent. In assays of pressor and antidiuretic activity it was observed consistently that the responses to the vasopressin analogue were of shorter duration than responses to lysine‐vasopressin of the s

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01931.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY

摘要:

A fully protected 27–42 hexadecapeptide of the variable region of myeloma immunoglobulin M603 was synthesized on a 2‐bromopropionyl‐resin by the solid phase method. Side reactions due to cyclization of glycyl‐2‐oxypropionylresin were studied under different reaction conditions. The loss of peptide chains at the dipeptide and tripeptide stages due to diketopiperazine formation was also examined. These side reactions were circumvented by using a combination of fragment and stepwise coupling methods. The synthesized protected peptide was removed from the resin in 85% yield by photolysis, and purified by crystallization and by chromatography on a Sephadex LH

ISSN:0367-8377    

DOI:10.1111/j.1399-3011.1979.tb01932.x

出版商:Blackwell Publishing Ltd    

年代:1979

数据来源: WILEY