Peptide Mapping Method Research Articles

Modified method for peptide mapping of collagen chains using cyanogen bromide-cleavage of protein within polyacrylamide gels

A highly efficient method for cyanogen bromide (CNBr)-mapping of collagen peptides in described. This method was developed based on polypeptide cleavage by CNBr within gel slices according to Barsh et al. ((1981) Collagen Relat. Res. 1, 543–548). The proposed method has the following advantages: (i) Analysis of both radiolabeled and unlabeled collagens is possible; (ii) CNBr-cleavage of polypeptides is performed in gel pieces which contain individual bands; (iii) The peptide losses are minimized, offering a more complete analysis of collagens including the low molecular weight CNBr-peptides.

Ｐｅｐｔｉｄｅ ｍａｐｐｉｎｇ法によるＥｕｈａｄｒａ属卵白せんたんぱく質の解析

Ｐｅｐｔｉｄｅ ｍａｐｐｉｎｇ法によるＥｕｈａｄｒａ属卵白せんたんぱく質の解析

Application of an automated tandem high-performance liquid chromatographic system to peptide mapping of genetic variants of human serum albumin

An automated tandem high-performance liquid chromatographic system was developed for peptide mapping of very large proteins. The method was applied systematically to the peptide mapping analysis of four genetic variants of human serum albumin, and amino acid substitutions in three of them could be identified. In two variants the amino acid substitutions were identified in both homozygote and heterozygote specimens. By this peptide mapping method at least 80% of the total amino acid residues can be screened rapidly. The method is especially useful for establishing the molecular basis of genetic relationships among protein variants found in different populations.

Two-dimensional peptide mapping by polyacrylamide-gel electrophoresis with limited proteolysis in SDS

The peptide mapping method described by Cleveland, et al. (1) was improved to a two-dimensional analysis applicable to minute amounts (less than 0.5 μg) of proteins. Radioiodinated proteins for analysis were purified by electrophoretic elution of the proteins from polyacrylamide gels into buffer containing 0.1% sodium dodecyl sulfate. The proteins were digested enzymatically in the presence of 0.1% sodium dodecyl sulfate and an excess of nonlabeled bovine serum albumin (0.2 mg/ml) relative to labeled substrate in order to attain reproducibility by maintaining a consistent substrate concentration among different samples. The peptides of these limited proteolytic products were resolved by two-dimensional polyacrylamide gel electrophoresis (isoelectric focusing followed by SDS-gels). The resulting 2D-peptide maps of murine and bovine albumin and a murine lymphocyte membrane peptide maps of murine and bovine albumin and a murine lymphocyte membrane protein, Tp100, showed excellent resolution and reproducibility.

Mammalian beta-adrenergic receptors. Structural differences in beta 1 and beta 2 subtypes revealed by peptide maps.

Photoaffinity labeling techniques using p-azido-m-[125I]iodobenzylcarazolol have recently demonstrated that both the beta 1- and beta 2-adrenergic receptor-binding subunits from mammalian tissues including heart, lung, and erythrocytes reside on peptides of Mr approximately equal to 62,000-64,000. In this study, a two-dimensional gel electrophoresis method for peptide mapping was used to investigate and compare the structure of beta 1 - and beta 2-adrenergic receptor subtypes. When the photoaffinity labeled Mr approximately equal to 62,000 peptides from the beta 2-adrenergic receptors of rat lung and erythrocyte are subjected to simultaneous proteolysis using Staphylococcus aureus V8 proteinase or papain, exactly the same peptide fragments are generated from each subunit. In contrast, when the Mr approximately equal to 62,000 peptide containing the beta 1-adrenergic receptor-binding subunit derived from the rat heart is proteolyzed simultaneously with the Mr approximately equal to 62,000 peptide containing the beta 2-adrenergic receptors from either lung or erythrocyte, the peptide fragments generated are distinctly different. Peptide maps of beta 1-adrenergic receptors from the myocardial tissue of different species (pig versus rat) yield slightly different maps while the maps derived from the beta 2-adrenergic receptors of hamster lung and rat lung or erythrocytes reveal no interspecies differences. These data suggest: 1) alterations in the primary structure of the beta-adrenergic receptor may be responsible for the pharmacological specificities characteristic of beta 1- and beta 2-adrenergic receptor subtypes; and 2) alterations in the primary structure of similar beta-adrenergic receptor subtypes across different species may relate to the magnitude of their phylogenetic differences.

The complete amino acid sequence of the light chain variable region of two monoclonal anti-p-azobenzene-arsonate antibodies bearing the cross-reactive idiotype

Two monoclonal anti- p-azobenzene-arsonate antibodies produced by cell fusion of A/J spleen lymphocytes were selected. It had previously been shown that they both expressed the cross-reactive idiotype (CRI) and that the amino terminal sequence of their heavy chain variable region differed by only one amino acid substitution within the first 55 residues, at residue 41 in the second framework region. A novel, sensitive peptide-mapping method had indicated that the light chain of these two antibodies differed by at least three amino acid substitutions. Here, the complete amino acid sequence of the light chain variable region is presented. There are only 3 amino acid substitutions between the two antibodies, located in the first and second complementarity determining regions and the third framework region respectively. Although the variable region of the light chains of these two monoclonal antibodies show such a high degree of homology they differ by 26 and 27 substitutions from the reference sequence of the light chain of CRI + anti-ABA serum antibodies. In addition, they are homologous to 4 other such CRI + monoclonal antibody light chain sequences published so far, in which only 2 of the above 3 substitutions are not represented. The contribution of the light chain to the CRI is discussed.

An efficient two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis method for simultaneous peptide mapping of protein contained in a mixture

A method for simultaneous peptide mapping of polypeptides contained in a mixture is presented. The polypeptides were first separated by conventional sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The strip of gel containing these unstained polypeptide bands was subsequently embedded perpendicular to the direction of electrophoresis in the stacking gel of a second gel. The proteolytic enzymes, loaded on top of the second gel, were brought in contact with the substrates through moving boundary electrophoresis. The peptides thus generated were then resolved by electrophoresis in a gradient gel. a polychromatic silverstaining method added an extra dimension to the identification and characterization of the peptides in the maps obtained in that specific peptides got specific colors. Moreover, the sensitivity of this method was illustrated by the demonstration that original quantities in the submicrogram range of nonradioactive proteins (exemplified here by the structural proteins of densonucleosis virus) largely sufficed for satisfactory maps. Other advantages of this procedure over current methods included (i) the elimination of the purification step (and consequently virtually no loss or contamination), (ii) that only the strict minimum of material (necessary for the ultimate visualization of the maps) had to be used, (iii) that no special two-dimensional electrophoresis equipment was needed, and (iv) the consistency, speed, and simplicity of the method.

Tryptic hydrolysis of inorcanic pyrophosphate modified by phosphate and O-phosphoethanolamine

By the peptide map method, a phosphorylated peptide has been isolated from a tryptic hydrolysate of phosphorylated yeast inorganic pyrophosphatase (I), and this is a direct proof of the formation of a covalent bond between (I) and phosphate in the course of this reaction. The isolation and analysis of the peptide from the tryptic hydrolysate shows that the phosphate acceptor is probably the aspartic acid residue 240 or 248. Analysis of a tryptic hydrolysate of (I) modified with O-phosphoethanolamine has shown that O-phosphoethanolamine forms an amide bond with the carboxy group of the same aspartic acid residue. In an alkaline medium, the phosphate residue migrates to the imidazole ring of a histidine residue, apparently that present in position 222.

A new mapping technique for collagen chains

A new, highly sensitive method for peptide mapping of collagen chains has been developed which utilizes a modification of the radioiodination technique in polyacrylamide gels described by Elder et al. (1977b). Optimal conditions include the use of the Bolton-Hunter reagent to produce 125I-labeled collagen of high specific activity and digestion of the radioiodinated collagen with the enzyme proteinase K, prior to resolution of the cleavage products by two-dimensional electrophoresis and chromatography. Unambiguous results were obtained by restricting comparison among collagens to a given set which was radioiodinated using the same procedure, i.e., in solution, or in a dried or hydrated gel. Iodination of collagens in solution, followed by proteinase K digestion, resulted in highly reproducible maps which were free of background contamination and which permitted characterization of chains with a defined mobility on SDS-PAGE after the iodination procedure.This technique has provided additional evidence that the α1, α2, and α3 chains of type V collagen are structurally unique. In addition, relationships among several fragments from pepsin-treated type IV collagen, which consists of two distinct chains, could be further elucidated.

A single amino acid substitution (Asp leads to Asn) in a phosphoglycerate kinase variant (PGK München) associated with enzyme deficiency.

The structural abnormality of the phosphoglycerate kinase variant, PGK München, associated with red cell enzyme deficiency and heat instability, was elucidated by a microscale peptide-mapping method. A single amino acid substitution, from aspartic acid in the normal enzyme to asparagine in the variant enzyme, was found. From the known amino acid sequence of normal human phosphoglycerate kinase, the substitution is in the aspartic acid residue located at 268th position from the NH2-terminal of the protein.

Primary structure of rabbit alpha-lactalbumin.

Rabbit alpha-lactalbumin was purified from the milk of New Zealand White rabbits. It was found to exist predominantly as a glycoprotein, containing 5 mol of glucosamine per mol of protein, as well as other sugars. The amino acid sequence of the protein was determined by sequenator analysis and carboxypeptidase digestion. There are 122 amino acids in the protein and a single carbohydrate moiety, probably attached to an asparagine residue at position 45. The C terminus of rabbit alpha-lactalbumin is one residue shorter than that of the other alpha-lactalbumins. Sequence comparisons indicate that the alpha-lactalbumin gene has been undergoing more frequent mutation than had previously been thought. A new method of preparative peptide mapping using 2,5-diphenyloxazole (PPO) fluor to detect peptides is described.

Peptide mapping of heterogeneous protein samples.

A simple two-dimensional electrophoretic method for peptide mapping of heterogeneous protein samples is presented. The reduced and denatured proteins of the mixture are separated in a first dimension by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis. After completion of the electrophoresis, the whole gel lane is equilibrated in stacking gel buffer and is transferred at right angles onto a second slab gel. A protease solution is overlayed on the gel lane and a partial proteolysis of the proteins to be analyzed is performed during the stacking phase of the second electrophoresis. The second electrophoresis resolves the characteristic pattern of peptides of each individual protein as a series of spots located below the original position of the undigested protein. The peptide maps of the following samples are presented as examples: protein P23 and P23* of bacteriophage T4, membranes of Dictyostelium discoideum, membranes of human erythrocytes, and 35S-labeled proteins of D. discoideum synthesized in vivo or in a cell-free wheat germ extract. In complex samples, up to 20 individual proteins can be analyzed at once and a protein comprising only 1% of the total sample generates a clearly identifiable peptide pattern. Good reproducibility of the patterns obtained allows the comparison of samples of different origins.

Inactivation of α-chymotrypsin by new bifunctional reagents : halomethylated derivatives of dihydrocoumarins

alpha-Chymotrypsin is rapidly and completely inactivated by a series of halomethylated derivatives of dihydrocoumarins at pH 7 and 25 degrees. The inactivation is pH-dependent and optimal at neutral pH; it is also more or less complete depending on the excess of inhibitor with respect to the enzyme. These compounds are substrates for alpha-chymotrypsin and, during the catalytic process, a latent alkylating function of the reagent is activated at the active site of the enzyme and reacts with some vicinal nucleophilic amino acid residues. The stoichiometry of the reaction of the corresponding radioactive reagents with the enzyme is slightly superior to one, but one histidine residue of alpha-chymotropsin is mainly modified. This histidine is identified as histidine-57 by the diagonal peptide mapping method. In comparison with other reagents, the efficiency of these suicide substrates" and particularly that one of a derivative (compound 2) carrying a substrate-like side chain is found to be very high.

Peptide mapping by limited proteolysis in sodium dodecyl sulfate and analysis by gel electrophoresis.

A rapid and convenient method for peptide mapping of proteins has been developed. The technique, which is especially suitable for analysis of proteins that have been isolated from gels containg sodium dodecyl sulfate, involves partial enzymatic proteolysis in the presence of sodium dodecyl sulfate and analysis of the cleavage products by polyacrylamide gel electrophoresis. The pattern of peptide fragments produced is characteristic of the protein substrate and the proteolytic enzyme and is highly reproducible. Several common proteases have been used including chymotrypsin, Staphylococcus aureus protease, and papain.

Methods for obtaining peptide maps of proteins on a subnanomole scale

A rapid method of peptide mapping by thin layer electrophoresis and chromatography is described that permits good maps to be produced from as little as 0.5 nmole of protein by means of conventional staining procedures with ninhydrin. The method can be made even more sensitive by prior amidination of the protein amino groups using methyl-[1- 14C]acetimidate, a simple synthesis of which is given. Because proteins generally contain many amino groups, autoradiographs of peptide maps of such radiolabeled proteins show a large number of spots in characteristic patterns, and the derivatization of the protein is easy and specific. A cheap and simply constructed apparatus for carrying out the thin layer electrophoresis is also described.

A study of bovine blood serum γ-globulin and of lymph gland tissue proteins with corresponding isoelectric points by the peptide map method

A study of bovine blood serum γ-globulin and of lymph gland tissue proteins with corresponding isoelectric points by the peptide map method

Micro-scale peptide mapping method for identification of variant proteins.

A micro-scale (for protein of the order of 10−9 mole) peptide mapping method in thin-layer cellulose is reported. Peptide maps of tryptic digests from glucagon, from normal and variant β-chains of human hemoglobin, from human glucose 6-phosphate dehydrogenase, and from human phosphoglycerate kinase showed satisfactory resolution; thus this method can be used for characterizing the structure of variant enzymes and proteins of 10−9 molar quantity.

An improved method for peptide mapping

An improved method for peptide mapping