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

Two peptic fragments (residues 37-88 and 43-88) of guinea pig myelin basic protein which are capable of inducing experimental allergic encephalomyelitis in Lewis rats were cleaved to shorter fragments with alpha-protease (Crotalus atrox proteinase, EC 3.4.24.1) and thermolysin (EC 3.4.24.4). The fragments were isolated, purified, and identified by amino acid composition and NH2- and COOH-terminal residues. The time courses of the reactions, monitored by thin layer electrophoresis of the digests, showed that alpha-protease cleaves peptide (43-88) initially at the Pro(71)-Gln(72) bond, and that the product peptides are subsequently attacked at the Arg(63) -Thr(64), Ser(74)-Gln(75), Arg(78)-Ser(79), and Ser(76)-Gln(80) bonds. No significant cleavages occurred at the -Leu, -Val, and -Ala bonds. These results are in striking contrast to those obtained previously by others workers with other peptide substrates, where selective cleavage at hydrophobic residues occurred. Thermolysin was found to attack peptide (37-88) at the Phe(42)-Phe(43) bond very rapidly; the product peptides were subsequently attacked at the His(60)-Ala(61), Ser(38)-Ile(39)-Tyr(67)-Gly(68), and Pro(84)-Val(85) bonds. These cleavages are compatible with the known specificity of this enzyme. Several of the fragments prepared with these two enzymes, peptides (43-71), (61-88), (75-88), and (72-84) have been used in other studies to locate the encephalitogenic site in the parent peptic peptide.
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PMID:Treatment of an encephalitogenic peptide from guinea pig myelin basic protein with alpha-protease and thermolysin. Isolation of fragments and determination of cleavage sites. 6 52

The myelin basic protein (BP) of pig brain was cleaved into its constituent tryptic peptides and the amino acid composition of each was determined. Those tryptic peptides that had not been sequenced previously were cleaved with dipeptidyl peptidases and the resulting dipeptides were trimethylsilated, separated by gas chromatography, and identified by mass spectrometry. Carboxypeptidases B and Y were used to establish the COOH-terminal sequences of some of the tryptic peptides; one tryptic peptide (sequence 76-92) was cleaved with thermolysin and the thermolytic peptides were analyzed. From the results of the present study together with those reported previously, it has been possible to determine the complete amino acid sequence of the protein. The protein consists of 172 residues and has a theoretical molecular weight of 18,604. Its amino acid sequence is identical with that reported for the homologous bovine protein with the following exceptions: Ser replaces (bovine) Ala2; His-Gly is inserted between Arg9 and Ser10; Ala replaces Ser45; His and Gly replace Gly76 and His77, respectively; Pro replaces Ser131 and Ser135; Ala is inserted between Gly142 and His143; and Gln replaces His143.
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PMID:Amino acid sequence of porcine myelin basic protein. 257 56

A monoclonal antibody (immunoglobulin G1) has been produced that reacts against myelin basic protein present in or extracted from the brains of many mammals-with certain important exceptions. Because of known species differences in amino acid sequences of basic protein and of certain peptide fragments, the binding site for this particular antibody appeared likely to include residues 130 to 137. Confirmation of this hypothesis was obtained by amino acid composition of the major immunoreactive peptides produced by thermolysin digestion of human basic protein and isolated by high-performance liquid chromatography.
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PMID:Species restriction of a monoclonal antibody reacting with residues 130 to 137 in encephalitogenic myelin basic protein. 616 47