Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.27 (thermolysin)
 1,894 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method was devised to isolate N-terminal peptide fragments from the polypeptide chains constituting thyroglobulin even in the case when the terminal amino groups are naturally blocked, for instance, acylated. Reduced and carboxymethylated hog thyroglobulin was first acetylated and digested with thermolysin. The blocked N-terminal peptide fragments were separated from the unblocked N-terminal fragments by column chromatography on Dowex 50, then on Dowex 1 after dinitrophenylation, and finally fractionated into ten fractions by paper chromatography after gel filtration on Sephadex G-10. Structural analyses by enzymic or partial acid hydrolysis of these peptide fractions failed to detect N-terminal acetyl amino acid. Instead, pyroglutamyl peptides including pyroglutamylleucine were found. By the same method, acetylated lysine and glycine were identified for chicken lysozyme and horse myoglobin, respectively. The use of thermolysin because of its unique specificity, and the possible relevance of the present result to the previous data on the N-terminal analysis of thyroglobulin are discussed.
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PMID:The presence of N-terminal pyroglutamyl residues in hog thyroglobulin. 93 62

The proteolytic specificity of thermolysin has been studied by quantitative analysis of an enzymic digest of dog myoglobin. Results confirm main specificities of thermolysin towards Phenylalanine, Isoleucine, Leucine or Tyrosine bonds; the influence of neighbourhood was also determined and the conclusions are in a good agreement with the known structure of the active site of thermolysin.
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PMID:[Specificity of thermolysin action on dog myoglobin]. 95 56

Myoglobin isolated from skeletal muscle of the platypus contains 153 amino acid residues. The complete amino acid sequence has been determined following cleavage with cyanogen bromide and further digestion of the four fragments with trypsin, chymotrypsin, pepsin and thermolysin. Sequences of the purified peptides were determined by the dansyl-Edman procedure. The amino acid sequence showed 25 differences from human myoglobin and 24 from kangaroo myoglobin. Amino acid sequences in myoglobins are more conserved than sequences in the alpha- and beta-globin chains, and platypus myoglobin shows a similar number of variations in sequence to kangaroo myoglobin when compared with myoglobin of other species. The date of divergence of the platypus from other mammals was estimated at 102 +/- 31 million years, based on the number of amino acid differences between species and allowing for mutations during the evolutionary period. This estimate differs widely from the estimate given by similar treatment of the alpha- and beta-chain sequences and a constant rate of mutation of globin chains is not supported.
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PMID:Studies on monotreme proteins. VII. Amino acid sequence of myoglobin from the platypus, Ornithoryhynchus anatinus. 96 22

Circular dichroism spectra have been obtained for albumin, alpha-chymotrypsinogen, collagen, concanavalin A, elastase, hemoglobin, histone f2b, alpha-lactalbumin, lactate dehydrogenase, beta-lactoglobulin, lysozyme, myoglobin, papain, ribonuclease A, and thermolysin in the presence of sodium dodecyl sulfate and dithiothreitol. While all spectra have the shape anticipated for a mixture of random coil and alpha helix, the intensities differ markedly ([theta]222 ranges from --1400 to --15 000 deg cm2/dmol). The variation in the circular dichroism can be quantitatively explained by a model which assumes that the arginyl, histidyl, and lysyl residues have an enhanced probability of propagating a helical segment in the presence of the detergent. The model also permits the computation of dimensional properties (unperturbed end-to-end distance and radius of gyration) for polypeptides of known amino acid sequence. Such computations have been performed for 67 proteins. The computed dimensions are compatible with experimental values and with the molecular weight dependence of the transport properties of the complexes. Furthermore, the model can account for the abnormal transport properties of the sodium dodecyl sulfate complexes formed by ribonuclease A, collagen fragments, and histones f2a1, f2a2, f2b, and f3. Even though some of the protein--sodium dodecyl sulfate complexes have helical contents as high as 50%, their overall conformation more closely approximates that of a random coil than a rod.
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PMID:Conformational properties of the complexes formed by proteins and sodium dodecyl sulfate. 96 36

The primary structure of the myoglobin of the prosimian Lorisidae Perodictius potto edwarsi (potto) was studied. Tryptic, chymotryptic, peptic, subtilisin and thermolysin peptides were aligned against the sequence of human myoglobin. Sixteen differences were found which were confirmed by sequential analysis. On comparison of the West African potto with two other prosimian myoglobins known so far, there were 12 differences between the potto and the galago (East African) and 18 differences between the potto and the sportive lemur (Madagascar).
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PMID:The myoglobin of primates. VII. Perodicticus potto edwarsi (potto). 109 64

After enzymatic digestion of chicken myoglobin by trypsin, chymotrypsin or thermolysin, the separation of peptides was performed by column chromatography on various ion exchange resins. Each peptide was purified by high-voltage paper electrophoresis or by chromatography either on paper or on ion-exchange resin, and its complete amino acid sequence was then determined by the combined dansyl-Edman procedure and by endopeptidase digestions. The whole globin was submitted to automatic Edman degradation using the Beckman sequencer. Residues have been positioned from overlaps of sequence data between tryptic (T), chymotryptic (C) and thermolysin (Th) peptides. The stepwise degradation of the whole globin confirmed the alignment of the N-terminal third of the molecule. The combination of these different approaches has led to the complete determination of the 153 residues sequence forming the polypeptide chain of chicken myoglobin. Comparison of the established chicken myoglobin structure with those from other species shows a conservation of structure, although the avian protein exhibits more variations in its amino acid sequence than has been found between other known myoglobins which all belong to mammalian species.
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PMID:The primary sequence of chicken myoglobin (Gallus gallus). 116 72

The flexibility plot of a protein lies on the observation that amino acid residues with the highest turn potential, i.e. located in highly mobile regions of protein surface, also possess the smallest volumes as well as the lowest hydrophobicities. The plot is generated by shifting a five residue window along the protein sequence and calculating the value of the hydrophobicity-volume product for consecutive quintuplets of amino acid residues. The concomitant occurrence of small volumes and low hydrophobicities results in very deep minima. A threshold value has also been introduced in order to discriminate significant minima. To substantiate the interpretation that the selected minima actually indicate very flexible segments of a protein (loops, turns, etc.), we have compared plots obtained for model proteins (lysozyme, myoglobin, ribonuclease, trypsin, thermolysin and T4 lysozyme) with X-ray thermal factors profiles available for the same proteins. When compared to thermal profiles, the majority of flexible segments evidenced by our plots have been found to be in agreement with regions characterized by high thermal factors. Results have also been discussed in the light of local organization possessed by examined proteins.
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PMID:Flexibility plot of proteins. 274 66

Myoglobin isolated from red muscle of the gummy shark M. antarcticus was purified by gel filtration and ion-exchange chromatography on carboxymethyl cellulose in 8 M urea-thiol buffer. Amino acid analysis and sequence determination showed 148 amino acid residues. The amino terminal residue is acetylated as shown by nuclear magnetic resonance and mass spectrographic analysis of an N-terminal peptide. There is a deletion of four residues at the amino terminal end as well as one residue in the CD interhelical area relative to other myoglobins. These overall differences were also found previously in myoglobin of Heterodontus portusjacksoni. The complete amino acid sequence has been determined following digestion with trypsin, chymotrypsin, thermolysin, staphylococcal protease and cyanogen bromide. Sequences of purified peptides were determined by the dansyl-Edman procedure. The amino acid sequence showed approximately 88 differences from mammalian, monotreme, bird and tuna myoglobins, slightly more than previously reported for H. portusjacksoni usually considered a more primitive animal. There were 24 residues common to both shark myoglobins that were different from those present in other myoglobins. The sequence has been compared to the myoglobin of yellowfin tuna and other myoglobins.
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PMID:Myoglobins of cartilaginous fishes. II. Isolation and amino acid sequence of myoglobin of the shark Mustelus antarcticus. 743 64

We show here that limited proteolysis can probe the structural and dynamic differences between the holo and apo form of horse myoglobin (Mb). Initial nicking of the polypeptide chain of apoMb (153 amino acid residues, no disulfide bonds) by several proteases (subtilisin, thermolysin, chymotrypsin and trypsin) occurs at the level of chain segment 89-96. In contrast, holoMb is resistant to proteolytic digestion when reacted under identical experimental conditions. Such selective proteolysis implies that the F-helix of native holoMb (residues 82 to 97) is disordered in apoMb, thus enabling binding and adaptation of this chain segment at the active site of the proteolytic enzymes for an efficient peptide bond fission. That essentially only the F-helix in apoMb is largely disrupted was earlier inferred from spectroscopic measurements and molecular dynamics simulations. The results of this study provide direct experimental evidence for this and emphasize therefore that limited proteolysis is a useful and reliable method for probing structure and dynamics of proteins, complementing other experimental techniques such as NMR and X-ray crystallography.
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PMID:Probing the conformational state of apomyoglobin by limited proteolysis. 904 59