Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The DD-carboxypeptidase-transpeptidase enzyme system in Streptomyces strain K15 consists of: (1) a membrane-bound transpeptidase capable of performing low DD-carboxypeptidase activity; and (2) a set of DD-carboxypeptidases: (a) membrane-bound, (b) lysozyme-releasable and (c) exocellular, having low transpeptidase activities in aqueous media and at low acceptor concentrations. The DD-carboxypeptidases are related to each other and may belong to the same pathway leading to enzyme excretion. A similar enzyme system occurs in Streptomyces strain R61 except that the membrane-bound DD-carboxypeptidase activity is low when compared with the membrane-bound transpeptidase activity. In Streptomyces rimosus the enzyme system consists almost exclusively of the membrane-bound transpeptidase and the levels of membrane-bound, lysozyme-releasable and exocellular DD-carboxypeptidases are very low.
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PMID:The peptidoglycan crosslinking enzyme system in Streptomyces strains R61, K15 and rimosus. 59 Feb 66

Streptomyces K15 possesses a set of exocellular and cell-bound D-alanyl-D-alanine carboxypeptidases. Four of them have been isolated to the stage where each enzyme preparation contains on single penicillin-binding protein. The exocellular 54000-Mr enzyme is extremely sensitive to benzylpenicillin and performs low transpeptidase activity on the carbonyl-donor/amino-acceptor tetrapeptide ACLLys(Gly)-DAla-DAla. The exocellular 40 000-Mr enzyme and the two lysozyme-releasable 40 000-Mr and 38 000-Mr enzymes are moderately sensitive to benzylpenicillin and have a high propensity to catalyse dimer formation from the aforementioned tetrapeptide monomer.
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PMID:On the DD-carboxypeptidase enzyme system of Streptomyces strain K15. 723 22

Transglutaminases (TGs) are known to exhibit remarkable specificities not only for the Q (or Gln) sites but also for the K (or Lys) sites of proteins with which they react. To gain further insight into K-site specificity, we examined the reactions of dansyl-epsilon-aminocaproyl-GlnGlnIleVal with three chemically and structurally well-characterized proteins (bovine pancreatic ribonuclease A, bovine pancreatic trypsin inhibitor, and chicken egg white lysozyme), as catalyzed by TG2, a biologically important post-translational enzyme. The substrates represent a total of 20 potential surface sites for acylation by the fluorescent Gln probe, yet only two of the lysine side chains reacted with TG2. While the K1 site of ribonuclease and the K15 site of the trypsin inhibitor could be readily acylated by the enzyme, none of the lysines in lysozyme were modified. The findings lead us to suggest that the selection of lysine residues by TG2 is not encoded in the primary amino acid sequence surrounding the target side chain but depends primarily on its being positioned in an accessible segment of the protein structure.
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PMID:Selectivity in the post-translational, transglutaminase-dependent acylation of lysine residues. 1922 23