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G Barany

Publications and source records attributed to G Barany.

At least 55 records · Page 3Linked to original sources
PubMed1995

Dynamic structure of a highly ordered beta-sheet molten globule: multiple conformations with a stable core.

The structure of [14-38]Abu, a variant of bovine pancreatic trypsin inhibitor (BPTI) with only the 14-38 disulfide bridge intact, has been analyzed by two-dimensional 1H and 1H-15N NMR. Except for the 18-24, 29-35 antiparallel beta-sheet, residues in all regions of the molecule give two exchange cross peaks for each 1H; for one residue, Gly 37, three exchange cross peaks are observed. The presence of exchange cross peaks indicates that the residues sample conformations that interconvert on a time scale of milliseconds or longer. Over 90% of the NMR spectra have been assigned, including backbone and side chain atoms and their exchange cross peaks. Analyses of chemical shifts, chemical exchange, hydrogen isotope exchange, and NOEs indicate that [14-38]Abu at pH 4.5 and 1 degree C is an ensemble of interconverting conformations, in all of which the 18-24, 29-35 antiparallel beta-sheet is native-like and intact. Outside the antiparallel beta-sheet, residues undergo local order/disorder transitions. The stable structure of [14-38]Abu is not in the vicinity of the 14-38 disulfide bond but rather is in the slow-exchange core. NOE analysis indicates that the main tertiary interactions involve hydrophobic contacts with the rings of Tyr 21, Tyr 23, and Tyr 35. As a model for early folding intermediates, the structure of [14-38]Abu suggests that BPTI folding is initiated by stabilization of a turn existing in the unfolded protein and involves both local and nonlocal hydrophobic interactions.

Amino Acid Sequence↗
PubMed1995

Partially folded, molten globule and molten coil states of bovine pancreatic trypsin inhibitor.

Three denatured states of bovine pancreatic trypsin inhibitor have been characterized, using two chemically synthesized analogues designed for study of folding intermediates. One analogue, [14-38]Abu, retains only the 14-38 disulphide. At pH 4.5-6 and 1-7 degrees C, [14-38]Abu is a highly ordered beta-sheet molten globule; it has the circular dichroism (CD), ANS-binding and folding kinetics of a molten globule; is partially folded by NMR analysis; and undergoes cooperative thermal denaturation. At low temperature [14-38]Abu also forms an acid state at pH 1.5, as well as a denatured state at pH 2.5. A second BPTI analogue with all three disulphide bridges eliminated, [R]Abu, lacks detectable secondary and tertiary structure but has stable hydrophobic surfaces and is collapsed. We term this species a 'molten coil'.

Anilino Naphthalenesulfonates↗
PubMed1995

Synthesis and characterization of indolicidin, a tryptophan-rich antimicrobial peptide from bovine neutrophils.

Indolicidin, a novel tryptophan-rich microbicidal tridecapeptide amide isolated originally from granules of bovine neutrophils, has been prepared by optimized manual and automated protocols of stepwise solid-phase synthesis with N alpha-9-fluorenylmethyloxycarbonyl (Fmoc) amino acid derivatives. Both standard polystyrene (PS) and polyethylene glycol-polystyrene (PEG-PS) graft supports were used in combination with handles that provide C-terminal peptide amides: 5-(4-Fmoc-aminomethyl-3,5-dimethoxyphenoxy)valeric acid (PAL) or 5-(9-Fmoc-aminoxanthen-2-oxy)valeric acid (XAL). Final deprotection/cleavage was carried out with reagent K, trifluoroacetic acid-phenol-water-thioanisole-1,2-ethanedithiol (82.5:5:5:5:2.5), or reagent B, trifluoroacetic acid-phenol-water-tri(isopropyl)silane (88:5:5:2), and related cocktails. Initial purities as high as 93% were obtained immediately following cleavage. In the largest-scale synthesis carried out, 0.8 g of HPLC-purified indolicidin (> 99% pure) was obtained, representing a 39% overall yield based on C-terminal Arg(Pmc) anchored to PAL-PS-resin. The main synthetic product, and some by-products, were characterized by analytical high-performance liquid chromatography (HPLC), sequencing, and fast atom bombardment mass spectrometry (FABMS). The antimicrobial potencies of natural and synthetic indolicidin, as determined by in vitro antibacterial and antifungal assays, were identical. Further, the reactivities of natural and synthetic peptides with anti-indolicidin antibody were indistinguishable.

Animals↗
PubMed1995

In vitro association of the phosphatidylinositol 3-kinase regulatory subunit (p85) with the human insulin receptor.

The insulin receptor, as a consequence of ligand binding, undergoes autophosphorylation of critical tyrosyl residues within the cytoplasmic portion of its beta-subunit. The 85 kDa regulatory subunit of phosphatidylinositol (PI) 3-kinase (p85), an SH2 domain protein, has been implicated as a regulatory molecule in the insulin signal transduction pathway. For the present study, glutathione S-transferase (GST) fusion proteins of p85 SH2 domains were used to determine if such motifs associate directly with the autophosphorylated human insulin receptor. The p85 N + C (amino plus carboxyl) SH2 domains were demonstrated to associate with the autophosphorylated beta-subunit, while neither the GTPase activator protein (GAP) N SH2 domain nor the phospholipase C-gamma 1 (PLC gamma 1) N + C SH2 domains exhibited measurable affinity for the activated receptor. The p85 N SH2 domain demonstrated weak association with the insulin receptor, while the p85 C SH2 domain alone formed no detectable complexes with the insulin receptor. The association of p85 N + C SH2 domains with the autophosphorylated receptor was competed efficiently by a 15-residue tyrosine-phosphorylated peptide corresponding to the carboxyl-terminal region of the insulin receptor, but not by phosphopeptides of similar length derived from the juxtamembrane or regulatory regions. The insulin receptor C domain phosphopeptide inhibited the p85 N + C SH2 domain-insulin receptor complex with an IC0.5 of 2.3 +/- 0.35 microM, whereas a 10-residue phosphopeptide derived from the insulin receptor substrate 1 (IRS-1) competed with an IC0.5 of 0.54 +/- 0.10 microM. These results demonstrate that, in vitro, there is an association between the p85 regulatory protein and the carboxyl-terminal region of the activated insulin receptor that requires the presence of both the N and C SH2 domains. Furthermore, formation of the p85/insulin receptor complex may lead to signaling pathways independent of IRS-1.

Adenosine Triphosphate↗
PubMed1995

Unfolded BPTI variants with a single disulfide bond have diminished non-native structure distant from the crosslink.

Backgound. NMR studies of denatured states, both fully unfolded and partially folded, give insight into the conformations and interactions favored in initial stages of folding, and in early intermediates formed during folding. We have characterized non-random structures favored in unfolded, reduced BPTI [1], and in partially folded BPTI [2]. Here, we report NMR-detected structure of two analogs of unfolded BPTI with one native 14-38 disulfide bond. Results. Analogs Y21A[14-38]Abu and Y23A[14-38]Abu, obtained by chemical synthesis of [14-38]Abu with Y21 or Y23 replaced by alanine, are models for unfolded BPTI with 14-38 the only disulfide. Compared to unfolded BPTI with all three disulfides broken, the unfolded 14-38 BPTI analogs have numerous differences, including loss of non-native, turn-like conformations for beta2 residues, diminished non-native aromatic-aliphatic NOEs, and increased intermediate chemical exchange of residues that have native-like conformations in partially folded BPTI. Although the Y21A and Y23A analogs have similar CD and NMR properties, specific differences in NOE patterns and in exchange broadening are observed. Conclusion. Changes in unfolded BPTI associated with formation of the 14-38 disulfide bond are consistent with less non-native structure, and more native-like structure, in residues composing the stable core of antiparallel beta-sheet in partially folded BPTI. Specific differences between Y21A[14-38]Abu and Y23A[14-38]Abu indicate that replacement of Y23 results in less ordered structure than replacement of Y21.

Journal Article↗
PubMed1993

Synthesis of phosphotyrosine-containing peptides and their use as substrates for protein tyrosine phosphatases.

Prior methods for the chemical synthesis of phosphotyrosine-containing peptides involved the incorporation of fully protected phosphoamino acids into the peptide chain or phosphorylation of free phenol side chains after peptide assembly is complete. The present work describes a novel and general methodology for the solid-phase synthesis of phosphopeptides, featuring direct incorporation of N alpha-(9-fluorenylmethyloxycarbonyl)-O-phospho-L-tyrosine (unprotected side chain). This technique obviated the formation of peptide byproducts containing tyrosine H-phosphonate, a previously unrecognized side reaction from literature phosphorylation/oxidation approaches. Phosphopeptides corresponding to the tyrosine phosphorylation site of adipocyte lipid binding protein were synthesized by the newer, preferred method. These peptides were purified and characterized by high-performance liquid chromatography (HPLC), capillary zone electrophoresis (CZE), amino acid analysis (AAA), fast atom bombardment mass spectrometry (FABMS), and 31P nuclear magnetic resonance (31P NMR). The synthetic peptides were tested as substrates for two distinct protein tyrosine phosphatases, rat brain protein tyrosine phosphatase (PTPase) and human acid phosphatase. Substrate specificity was measured at pH 6.0 and 37 degrees C, using a colorimetric assay for released inorganic phosphate. Kinetic analysis revealed that both the rat brain PTPase and the human adipocyte acid phosphatase catalyzed peptide dephosphorylation but with different rates and affinities. The rat brain PTPase displayed classical Michaelis-Menten kinetics, with Km's of 68 +/- 9 microM and 42 +/- 11 microM and kcat/Km values of 4.9 x 10(5) s-1 M-1 and 6.9 x 10(5) s-1 M-1 determined for phosphorylated peptides of lengths 4 and 10 residues, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

4-Nitrophenylphosphatase↗
PubMed1993

Acidolytic cleavage of tris(alkoxy)benzylamide (PAL) "internal reference" amino acyl (IRAA) anchoring linkages: validation of accepted procedures in solid-phase peptide synthesis (SPPS).

Under the normal conditions of acidolytic cleavage/deprotection of tris(alkoxy)benzylamide (PAL) anchoring linkages in Fmoc solid-phase peptide synthesis (SPPS), product release occurs by a straightforward single-step pathway. A recently reported cleavage of the NH--alpha CH bond of an amino acyl residue adjacent to PAL [see Int. J. Peptide Protein Res. 38, 146-153 (1991)] could not be confirmed in novel experiments incorporating a double "internal reference" amino acid (IRAA) design. The results of the present work revalidate the widely accepted application of IRAAs to monitor yields in SPPS, and confirm the reliability of PAL methodology for the preparation of C-terminal peptide amides.

Amino Acids↗
PubMed1991

Cyclization of disulfide-containing peptides in solid-phase synthesis.

Disulfide-containing peptides may be obtained in good yields and purities when oxidations are carried out on peptide chains anchored to polymeric supports used for solid-phase synthesis. Such approaches take advantage of the pseudo-dilution phenomenon which favors intramolecular processes. A variety of procedures have been demonstrated using the related model peptides Ac-Cys-Pro-D Val-Cys-NH2 and Ac-Pen-Pro-D Val-Cys-NH2 (which both readily assume a type II beta-turn conformation that becomes stabilized by a 14-membered disulfide-containing intramolecular ring), and oxytocin (conformationally mobile 20-membered disulfide ring). Both Boc and Fmoc were used for N alpha-amino protection, the beta-thiols of cysteine or penicillamine were blocked by S-acetamidomethyl (Acm), S-9-fluorenylmethyl (Fm), or S-trityl (Trt), and compatible anchoring linkages included HF-labile 4-methylbenzhydrylamide (MBHA), TFA-labile tris (alkoxy)benzylamide (PAL), and photolabile o-nitrobenzylamide (Nonb). Assemblies of linear sequences proceeded smoothly, and polymer-supported oxidations were carried out in a variety of ways either directly or after deblocking to the resin-bound dithiol. Chains were released from the support without substantial damage to the disulfide bridges, and overall yields were as high as 60-90%.

Amino Acid Sequence↗
PubMed1990

Practical approach to solid-phase synthesis of C-terminal peptide amides under mild conditions based on a photolysable anchoring linkage.

Several 3-nitro-4-(N-protected aminomethyl)benzoic acids; with protection provided by tert.-butyloxycarbonyl (Boc), 9-fluorenylmethyloxycarbonyl (Fmoc), trifluoroacetyl (Tfa), dithiasuccinoyl (Dts), or phthaloyl (Phth), have been prepared by reproducible routes. Synthesis of Dts-handle 6 illustrates some particularly novel and efficient chemistry, and is preferred over more intricate routes to Boc-handle 3 and Fmoc-handle 4. The five handles were each evaluated for their application to the synthesis of peptide amides. Coupling onto amino-functionalized supports provided a general starting point for peptide chain assembly. The handle amino function was deblocked (Boc, Fmoc, Dts), the C-terminal residue was coupled as its N alpha-protected free acid, and ultimately the ortho-nitrobenzylamide anchorage linkage was cleaved photolytically to give the corresponding amide. Starting with handles 3, 4, and 6, several free and protected peptide amides were synthesized.

Amides↗
PubMed1990

Orthogonal solid-phase synthesis of human gastrin-I under mild conditions.

An approach to the solid-phase segment condensation synthesis of the 17-peptide amide human gastrin-I has been developed. N alpha-amino and side-chain protection were provided by 9-fluorenylmethyloxycarbonyl (Fmoc) and tert.-butyl groups, and a series of anchors cleavable under mild conditions were used. The N-terminal pentapeptide pGlu-Gly-Pro-Trp-Leu-OH was prepared using a p-alkoxybenzyl ester linkage made by a preformed handle strategy. Cleavage, in 65% yield, was with the new Reagent M: CF3COOH-CH2Cl2-beta-mercaptoethanol--anisole (70:30:2:1), which was optimized to preserve the labile tryptophan residue. A new preformed handle procedure expedited solid-phase synthesis of the protected "middle" hexapeptide, Fmoc-(Glu(OtBu]5-Ala-OH, anchored as an o-nitrobenzyl ester. Chains were not lost during this assembly, and final photolytic cleavage (350 nm) in toluene--CF3CH2OH (4:1) occurred in 59% yield. Both protected intermediates were purified by simple gel filtration, whereupon they were shown to be pure by analytical HPLC, and gave satisfactory NMR and FABMS spectra. Last, the C-terminal hexapeptide, Tyr(tBu)-Gly-Trp-Met-Asp(OtBu)-Phe, was assembled on a tris(alkoxy)benzylamide "PAL" support. For the polymer-supported segment condensation, the middle and N-terminal pieces were added respectively in greater than 98% and 89% yields (judged by amino acid analysis and solid-phase sequencing), by overnight couplings in N,N-dimethylformamide (DMF) mediated by benzotriazolyl N-oxytrisdimethylaminophosphonium hexafluorophosphate (BOP) in the presence of 1-hydroxybenzotriazole (HOBt) and N-methylmorpholine (NMM). Racemization was 4% and 11% respectively at Ala and Leu. Cleavage with Reagent M followed by reversed-phase chromatography gave pure gastrin-I in an overall 30% isolated yield. These results compare favorably with those from a stepwise assembly.

Amino Acid Sequence↗
PubMed1990

Solid-phase synthesis of peptides with C-terminal asparagine or glutamine. An effective, mild procedure based on N alpha-fluorenylmethyloxycarbonyl (Fmoc) protection and side-chain anchoring to a tris(alkoxy)benzylamide (PAL) handle.

Attempts to anchor Fmoc-asparagine or glutamine as p-alkoxybenzyl esters for solid-phase peptide synthesis are fraught with difficulties. A convenient and effective method to prepare peptides with C-terminal asparagine or glutamine involves quantitative attachment of N alpha-Fmoc-C alpha-tert.-butyl aspartate or glutamate via the free omega-carboxyl groups to a tris(alkoxy)benzylamino (PAL) support. Chain elongation proceeds normally by standard Fmoc chemistry, and treatment with acid, e.g., CF3COOH--CH2Cl2, 90 min at 25 degrees, releases the desired peptides in greater than 95% yields without side reactions at the C-terminus. Feasibility of the approach has been demonstrated by the syntheses of the C-terminal octapeptide from human proinsulin, H-Leu-Ala-Leu-Glu-Gly-Ser-Leu-Gln-OH, and the serum thymic factor pGlu-Ala-Lys-Ser-Gln-Gly-Gly-Ser-Asn-OH.

Amino Acids↗
PubMed1989

Inhibition of N-nitrosodiethylamine carcinogenesis in mice by naturally occurring organosulfur compounds and monoterpenes.

Naturally occurring compounds belonging to two chemical groups were studied for their capacities to inhibit N-nitrosodiethylamine (NDEA)-induced carcinogenesis in female A/J mice. One group consists of organosulfur compounds found in Allium species, including garlic, onions, leeks, and shallots, and the other, two monoterpenes, i.e., D-limonene and D-carvone. In an initial experiment, in which organosulfur compounds were investigated, diallyl disulfide, allyl mercaptan, and allyl methyl disulfide were found to produce a marked inhibition of NDEA-induced neoplasia of the forestomach when the test compounds were administered p.o. 96 and 48 h prior to NDEA. The most potent was diallyl disulfide which reduced forestomach tumor formation by more than 90%. Pulmonary adenoma formation also was inhibited but to a considerably lesser extent, i.e., about 30%. In three additional experiments, test compounds were given p.o. either 15 min or 1 h prior to NDEA. Under these conditions diallyl disulfide and allyl mercaptan again inhibited forestomach tumor formation substantially, i.e., greater than 75%, and pulmonary adenoma formation marginally, i.e., less than 20%. In these experiments D-limonene and D-carvone were tested and reduced forestomach tumor formation by slightly over 60% and pulmonary adenoma formation by about 35%. The results of these studies provide evidence of an increasing diversity of naturally occurring compounds having the capacity to inhibit nitrosamine carcinogenesis.

Allium↗
PubMed1989

Inhibition of soybean lipoxygenase and mouse skin tumor promotion by onion and garlic components.

Onion and garlic essential oils were previously shown to inhibit mouse skin tumor promotion, as were the enzymes, lipoxygenase, and cyclooxygenase. In the present study, the inhibition of soybean lipoxygenase (EC 1.13.11.12) by onion and garlic components and related compounds was investigated. The IC50 values as well as the kinetic inhibition constants were determined for the most active compounds. Di-(1-propenyl) sulfide, an analog of the substrate moiety required for oxygenase action, was the only irreversible inhibitor observed with Ki = 59 microM and k3 = 0.53/min. Inhibition in the presence of substrate was uncompetitive at 88 and 132 microM linoleic acid with Ki = 129 microM. At 173 microM linoleic acid, however, inhibition was competitive with Ki = 66 microM. Dially trisulfide, allyl methyl trisulfide, and diallyl disulfide were competitive inhibitors, while 1-propenylpropyl sulfide and (E, Z)-4,5,9-trithiadodeca-1,6,11-triene 9-oxide (ajoene) were mixed inhibitors. Nordihydroguaiaretic acid (NDGA), the most potent lipoxygenase inhibitor, was a competitive inhibitor with Ki = 0.29 microM. The results indicate a relative potency of inhibition for structural features in the following order: di(1-propenyl) sulfide greater than an alkenyl trisulfide greater than an alkenyl disulfide. Di(n-propyl) disulfide, a major onion oil component, inhibited neither lipoxygenase nor promotion. Di(1-propenyl) sulfide and ajoene inhibited both. This suggests that the inhibition of lipoxygenase may be involved in antipromotion.

Allium↗
PubMed1988

Effects of organosulfur compounds from garlic and onions on benzo[a]pyrene-induced neoplasia and glutathione S-transferase activity in the mouse.

In the present study, eight organosulfur compounds from garlic and onions were studied for their inhibitory effects on benzo[a]pyrene (BP)-induced neoplasia of forestomach and lung of female A/J mice when administered 96 and 48 h prior to carcinogen challenge. These compounds had one, two or three linearly connected sulfur atoms. They included the four allyl group-containing derivatives: allyl methyl trisulfide (AMT), allyl methyl disulfide (AMD), diallyl trisulfide (DAT), and diallyl sulfide (DAS), and also four corresponding saturated compounds in which propyl groups were substituted for the allyl groups. All four allylic compounds inhibited BP-induced neoplasia of the forestomach. The saturated analogs were almost without inhibitory activity, indicating the importance of the allyl groups. DAT, which contains two allyl groups, was more potent than AMT, which contains only one allyl group, thus providing further evidence for the role of allyl groups in the inhibitory effects observed. DAS and AMD, but not DAT or AMT, inhibited pulmonary adenoma formation. The fact that in the lung the monosulfide and disulfide inhibited, but the trisulfide did not inhibit, indicates that the number of sulfur atoms in the molecule can control the organ sites at which protection against carcinogenesis will occur. All four allylic compounds induced increased glutathione S-transferase (GST) activity in the forestomach, but varied in their capacity to induce GST in lung, liver and small bowel. Their saturated analogs produced little or no induction. In evaluating relationships between diet and cancer, it would be useful to consider the possible role of garlic and onion organosulfur compounds as protective agents. In addition, further studies of this class of chemicals might lead to the identification and development of useful new chemopreventive compounds.

Allium↗
PubMed1987

Mild, orthogonal solid-phase peptide synthesis: use of N alpha-dithiasuccinoyl (Dts) amino acids and N-(iso-propyldithio)carbonylproline, together with p-alkoxybenzyl ester anchoring linkages.

Several N alpha-dithiasuccinoyl (Dts) amino acids (1) have been esterified without racemization by use of either N,N'-dicyclohexylcarbodiimide or 1-(3-dimethylamino-propyl)-3-ethylcarbodiimide hydrochloride, each in the presence of 4-dimethylaminopyridine (0.1 equiv.), to 2, 4, 5-trichlorophenyl 4'-hydroxymethylphenoxyacetate (10) or the corresponding propionate (11). The resultant handle derivatives (8,9) were purified and then quantitatively attached onto aminomethyl supports by couplings using as solvent N,N-dimethylformamide containing 1-hydroxybenzotriazole (0.1 M). This methodology facilitates anchoring of Dts-amino acids as p-alkoxybenzyl esters, which can be cleaved in good yields by trifluoroacetic acid-dichloromethane (1:1) at 25 degrees. Model experiments established that quantitative thiolytic removal (greater than 99.8%) of the Dts group occurs with (i) beta-mercaptoethanol (0.5 M)-N,N-diisopropylethylamine (0.5 M) in dichloromethane, 2 X 2 min; (ii) N-methylmercaptoacetamide (0.5 M)-N-methylmorpholine (0.5 M) in dichloromethane, 2 X 2 min; and (iii) N-methylmercaptoacetamide (0.5 M)-1-hydroxybenzotriazole (0.1 M) in N,N-dimethylformamide, 2 X 2 min. The susceptibility of the Dts functionality to nucleophiles was also defined, including demonstration of tertiary amine-catalyzed hydantoin formation from Dts-dipeptidyl units, but side reactions from these processes are entirely avoided under appropriate conditions relevant to peptide synthesis. These observations were exploited to devise efficient, racemization-free solid-phase syntheses of a number of model peptides in high yields and purities, including L-leucyl-L-alanylglycyl-L-valine, H-Gly6-Val-OH, H-Met-Ala-Gly-OH, methionine-enkephalin, and bradykinin.

Amino Acids↗
PubMed1987

An acid-labile anchoring linkage for solid-phase synthesis of C-terminal peptide amides under mild conditions.

A series of polymer-supported benzylamides substituted with one to three alkoxy groups in the ring positions were prepared and shown to give carboxamides upon treatment with acid. Based on the initial screening, the bis(o-methoxy)-p-alkoxybenzylamide anchoring linkage was selected for a detailed evaluation of its suitability for solid-phase synthesis of C-terminal peptide amides. The handle derivative 5-[(2' or 4')-Fmoc-aminomethyl-3',5'-dimethoxyphenoxy]valeric acid (1) was prepared in seven facile steps [purification of intermediates unnecessary; overall yield 15% for crystalline product, which is a mixture of positional isomers], and was quantitatively coupled onto amino group-containing supports by use of N,N'-dicyclohexylcarbodiimide plus 1-hydroxybenzotriazole in N,N-dimethylformamide. Stepwise elaboration of peptide chains proceeded smoothly with both N alpha-9-fluorenyl-methyloxycarbonyl (Fmoc) and N alpha-dithiasuccinoyl (Dts) amino acids, and final cleavage of tert.-butyl side-chain protecting groups and of the anchoring linkage occurred readily in trifluoroacetic acid-dichloromethane (7:3) at 25 degrees. The methodology was demonstrated by the syntheses of H-Trp-Asp-Met-Phe-NH2 (tetragastrin) and H-Tyr-Gly-Gly-Phe-Met-NH2 (methionine-enkephalinamide), both with high yields and purities.

Amides↗
PubMed1987

Solid-phase peptide synthesis: a silver anniversary report.

It has been a quarter of a century since Merrifield's initial report on solid-phase peptide synthesis. The field has matured significantly in recent years with a better understanding of the underlying chemistry. This is reflected by new, milder orthogonal protection schemes and more efficient coupling methods, some of which have been incorporated into automated systems. Advances in purification, especially high performance liquid chromatography, have had a major impact. The efficacy of these improvements has been demonstrated by an impressive litany of applications to biological problems.

Methods↗