Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The complete amino acid sequence of ribosomal protein L34 has been established by improved micro techniques with 3 mg of the lyophilized protein. The protein was digested with trypsin, thermolysin and chymotrypsin and the resulting peptides were isolated from fingerprints performed on cellulose thin-layer plates. The amino acid sequences of the peptides were determined by the combined micro dansyl-Edman technique using 5 - 10 nmol per sample. Aspartic acid and glutamic acid were distinguished from their amides by use of the color reaction of ninhydrin with the respective amino acid phenylthiohydantoins.
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PMID:The sequence determination of a protein in a micro scale: the sequence analysis of ribosomal protein L34 of Escherichia coli. 78 33

The purification and characterization of two related peptides making up the glutamine binding site of formylglycinamide ribonucleotide amidotransferase from chicken liver have been presented. An amino acid residue(s) involved in binding glutamine to the enzyme was selectively labeled with [14C]iodoacetate. The labeled enzyme was reduced, carboxymethylated, and degraded by trypsin to a large radioactive peptide that yielded on acid hydrolysis only cysteine as a radioactive carboxymethylated derivative. The tryptic peptide was further digested with a protease from Streptomyces griseus. Two radioactive fractions (I and II) were obtained by gel filtration on Sephadex G-25. Furthermore, two 14C-containing peptides have been isolated from fraction I by the aid of ion exchange chromatography on AG 1-X2, AG 50W-X2 and DEAE-cellulose. Upon acid hydrolysis both peptides yielded only carboxymethylcysteine (CMCys), cystine, glycine, valine, aspartic acid, and glutamic acid. The partial sequences of the amino residues in these peptides, which are located at the glutamine binding site, have been established by the dansyl-Edman method. The sequences of amino acids of peptides a and b are Gly-Val-Cys([14C]CM)-Asp-Asx-Cys(CM)-Glx...and Gly-Val-Cys([14C]CM)-Asx-Asx..., respectively. The two peptides are undoubtedly derived from the same segment of the original protein.
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PMID:Glutamine active site of formylglycinamide ribonucleotide amidotransferase. 2. Amino acid sequence of labeled peptides. 84 8

A phosphorylated polypeptide (E4) of molecular weight 5000-6000, has been isolated from bovine embryonic enamel by Bio-Gel P-10 gel filtration and DE-52 ion-exchange chromatography. The peptide contains three serine residues all of which are phosphorylated. All three O-phosphoserine residues are in glutamic acid-O-phosphoserine-tyrosine sequences that are distributed relatively evenly along the polypeptide chain. Although it was not possible to sequence the entire polypeptide chain directly by automatic peptide sequencing, a partial sequence and peptide map was constructed on the basis of the sequence and composition of peptides derived by cyanogen bromide, trypsin and chymotrypsin digestion. The presence of glutamic acid, tyrosine and leucine adjacent to and near the O-phosphoserine residues may be important in calcium binding and in mineralization.
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PMID:Isolation, characterization and partial amino acid sequence of a phosphorylated polypeptide (E4) from bovine embryonic dental enamel. 88 76

Of four glycoproteins isolated from guinea pig testes, two were aspermatogenic (types I and IV) and two (types II and III) were inactive. The glycoproteins were rich in carbohydrate, varying from 41.5% to 49.5% carbohydrate by weight. Each glycoprotein had a unique amino acid composition, but in general low levels of tyrosine, tryptophan, and basic amino acids were found along with relatively high contents of serine, threonine, glutamic acid, and proline. Types I and IV glycoproteins were remarkably stable; their aspermatogenic activity was not affected by urea, trypsin, or heating at 100 degrees C in water or in 1 M HCl for 15 min. Carbohydrate analysis revealed little difference in the monosaccharide compositions of types I and IV glycoproteins, except that only the type I contained sialic acid. In contrast, types II and III glycoproteins lacked sialicacid and fucose and contained much less mannose. Both N-acetylglucosamine and N-acetylgalactosamine were present in all four glycoproteins, and they dominated in the types II and III. Fucose and at least 20-25% of the galactose appeared to occupy terminal positions in type IV glycoprotein as shown by their release after 15 min hydrolysis in 1 M HCl. All of the glycoproteins contained a relatively high percentage of galactose by weight, from 12.6 to 19.3%. The molecular weights of the glycoproteins were estimated by sodium dodecyl sulfate gel electrophoresis to be 47000, 105000 and 18000 respectively for the types I, II, and IV; type III glycoprotein showed two major bands, with molecular weights of 41500 and 22800. All the above molecular weight values are probably overestimated because of high carbohydrate content. The molecular weight of type IV glycoprotein was found to be 13000 by ultracentrifugation; a corrected value of 29000 was calculated for type I glycoprotein.
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PMID:Experimental allergic aspermatogenic orchitis. IV. Chemical properties of sperm glycoproteins isolated from guinea pig testes. 95 93

Nuclear basic protein from ejaculated human spermatozoa were labelled with iodo[14C1]acetic acid and fractionated by ion-exchange chromatography into several pools (named A-K). Gel electrophoresis indicated that the minor protamine components, were present in pool D and that, of the major protamine components, component 1 (pools E, F, G, H) was well separated from the unresolved mixture of component 2 and component 3 (pools I, J, K). Pools G and J were free of other contaminants. Pools D, G, and J produced different radioactive peptides on digestion with trypsin and with thermolysin, and also had quite distinct amino acid compositions. This suggests that the heterogeneity of human protamines is caused by differences in amino acid sequence. Major component 1 also seems to be heterogenous, since it was found in two distinct peaks (pools E and G), but post-translational modification as a cause of the two types of component 1 has not been ruled out. Although all the human protamine components are similar to other mammalian protamines in containing half-cysteine and tyrosine, they also have unique common features such as high histidine and high glutamic acid contents.
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PMID:The heterogeneity of the protamines from human spermatozoa. 95 98

Agrocin 84, produced by Agrobacterium radiobacter K84, inhibited ribonucleic acid, deoxyribonucleic acid, and protein synthesis and amino acid transport in a susceptible, virulent strain of A. tumefaciens H-38-9. Cell motility was immediately stopped by action of the agrocin, 50% of the cells were killed within 15 min of contact, and the remainder were inhibited. Agrocin 84 is trypsin and pepsin resistant, but chemical analysis indicated a small peptide with a molecular weight of 2,500 containing six different amino acids, including nine molecules of glutamine or glutamic acid and seven molecules of serine.
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PMID:Chemical nature of agrocin 84 and its effect on a virulent strain of Agrobacterium tumefaciens. 98 92

A human alpha1-antitrypsin variant protein was purified to homogeneity from homozygous variant subjects (Pi-ZZ) who had a deficiency of plasma trypsin inhibitory capacity. Molecular weight, specific trypsin inhibitory capacity, and immunologic activity of the variant protein were identical to those of normal. Amino acids, N-acetylglucosamine, and hexose contents were closely similar in the normal and variant proteins, but the sialic acid content in the variant protein was significantly lower than normal. The structural difference between the normal and the variant alpha1-antitrypsin was elucidated by fingerprinting of their tryptic peptides. Two amino acid substitutions, i.e., glutamic acid in the normal protein to lysine in the variant protein, and glutamic acid in the normal protein to glutamine in the variant protein, were found.
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PMID:Molecular abnormality of human alpha1-antitrypsin variant (Pi-ZZ) associated with plasma activity deficiency. 108 27

Two albumins, albumin A from C3H mice and albumin C isolated from descendents of the wild mice in which the variant was first uncovered, were found to differ in their electrophoretic properties. Albumin C was shown to bind two more H+ ions than albumin A at pH 5.4. Peptide mapping after trypsin digestion revealed that albumin C had three peptides (TP-C1, TP-C2, and TP-C3) which were missing in albumin A. The latter likewise had a peptide (TP-A1) which was not found in albumin C. An amino acid analysis of the variant peptides suggests that TP-A1 had been split into TP-C1 and TP-C2 on digestion with trypsin, because a glutamic acid in TP-A1 was replaced by a lysine. This change would also appropriately alter the electrophoretic properties of albumin C. No obvious counterpart was discovered for TP-C3 of albumin C in albumin A.
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PMID:Structural differences between albumin A and albumin C of the house mouse, Mus musculus. 125 5

Recent evidence indicates that chromatin accessibility to transcription factors is of regulatory significance. The polyanion heparin is known to increase chromatin accessibility to DNAase I and to stimulate both RNA and DNA synthesis. In the present study, chromatin structure and its modification by polyanions were examined by using trypsin and micrococcal nuclease as probes. Both heparin and poly(glutamic acid) were found to be equivalent to trypsin digestion of histones in their ability to increase nuclease accessibility in chromatin. However, no increase in nuclease accessibility was observed when trypsin-digested chromatin was further treated with heparin, indicating that polyanions and trypsin are not additive in their effects on chromatin accessibility. Moreover, sucrose-gradient analysis demonstrated that heparin binds tightly to intact nucleosomes but not to trypsin-digested nucleosomes. These data suggest that polyanions interact predominantly with the trypsin-sensitive lysine and arginine residues in histone H1 and the N-terminal segments of the core histones. The possible relevance of these results to the chromatin structure of actively transcribed regions is discussed.
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PMID:Heparin increases chromatin accessibility by binding the trypsin-sensitive basic residues in histones. 128 84

This paper summarises results and conclusions from experiments with renal Na/K-ATPase, utilising proteolytic digestion to define minimal peptide structures involved in cation occlusion and chemical modification with dicyclohexylcarbodiimide (DCCD) to investigate the role of carboxyl groups and location of K (Rb) and/or Na binding residues. Extensive digestion with trypsin or non-selective proteases in the presence of Na or Rb and absence of divalent cations reveals an essential C-terminal 19Kd fragment of the alpha chain (N-terminal asn 830) and indicates that occlusion sites of Na or K ions must reside within transmembrane segments. The bulk of the beta chain is not involved. Kinetics of inactivation of Rb or Na occlusion and covalent labelling with DCCD indicate that each of two Rb(K) or Na sites contains a carboxyl group. The third Na site may contain only neutral ligating groups. One carboxyl group is located on the 19Kd fragment and the other on tryptic fragment of about 9Kd. When cyanogen bromide was used to digest labelled alpha chain, glu 953 was found to be labelled in a Rb-protectable fashion. In tryptic "19Kd-membranes", fragments containing all putative transmembrane segments of the alpha chain have been identified (i.e. 19, 10.9, 8.7 and 8.0 Kda respectively). The cation occlusion "cage" is apparently composed of ligating groups from different trans-membrane segments, including segments of the 19Kd fragment. Construction of models is hampered by the fact that the number of the transmembrane segments is still uncertain, particularly in the crucial C-terminal domain. Alternative ways of arranging the tryptic fragments across the membrane are discussed.
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PMID:Identification of the cation binding domain of Na/K-ATPase. 133 62


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