The chemical structure of lysozyme substrates and their cleavage by the enzyme

1967 ◽  
Vol 167 (1009) ◽  
pp. 402-415 ◽  
Keyword(s):  
Paper Chromatography ◽  
Active Site ◽  
Cell Walls ◽  
Chemical Structure ◽  
Enzymic Activity ◽  
Fluorescence Studies ◽  
Tryptophan Residues ◽  
Micrococcus Lysodeikticus ◽  
Hydrolysis Of ◽  
Long Chain

The isolation of a disaccharide, N -acetyl- β -D-glucosaminyl-(1 → 4) N -acetylmuramic acid ( NAG-NAM ) and a corresponding tetrasaccharide, from lysozyme digests of Micrococcus lysodeikticus cell walls, is described. These compounds have been used for the study of the enzymic activity of lysozyme. Digestion of the tetrasaccharide into disaccharide has been followed by ( a ) paper chromatography, ( b ) colorimetry, using the Morgan-Elson reaction, and ( c ) polarimetry. Lysozyme was found to catalyse transglycosylation in addition to hydrolysis, and it is proposed that hydrolysis of the tetrasaccharide does not proceed by direct cleavage, but by a transfer mechanism, via long chain oligosaccharides. N -acetyl-glucosamine and closely related oligosaccharides strongly inhibit the enzymic activity of lysozyme. Fluorescence studies show that these inhibitors interact with the tryptophan residues in the active site of the enzyme.

scholarly journals Bacteriolytic enzymes from Staphylococcus aureus. Specificity of action of endo-β-N-acetylglucosaminidase

1970 ◽  
Vol 120 (4) ◽  
pp. 735-744 ◽  
Author(s):  
T. Wadström ◽  
K. Hisatsune
Keyword(s):  
Amino Acids ◽  
Staphylococcus Aureus ◽  
Acid Hydrolysis ◽  
Cell Walls ◽  
Muramic Acid ◽  
Bacteriolytic Enzymes ◽  
Bacteriolytic Enzyme ◽  
Enzyme Digest ◽  
Micrococcus Lysodeikticus ◽  
Hydrolysis Of

The bacteriolytic enzyme with an isoelectric point of 9.5 that is produced by all strains of Staphylococcus aureus investigated was purified from strain M18 (Wadström & Hisatsune, 1970). This enzyme released reducing groups from cell walls of Micrococcus lysodeikticus and was thus shown to be a bacteriolytic hexosaminidase. Although dinitrophenylation and acid hydrolysis of cell walls hydrolysed by a partially purified enzyme gave DNP-alanine and DNP-glycine from staphylococcal peptidoglycan, which indicated the presence of a peptidase and probably also an N-acetylmuramyl-l-alanine amidase, hydrolysis of cell walls by the extensively purified enzyme did not give any DNP-amino acids. The enzyme digest was purified by Amberlite CG-120 and Sephadex G-10 chromatography. Reduction by sodium borohydride of the disaccharide obtained was followed by acid hydrolysis and paper chromatography. Glucosamine completely disappeared after this treatment and a new spot identical with glucosaminitol appeared. The muramic acid spot remained unchanged. The purified enzyme was found to be devoid of exo-β-N-acetylglucosaminidase activity. These results are compatible with the action of a bacteriolytic endo-β-N-acetylglucosaminidase. It is also proposed that this enzyme is probably identical with the staphylococcal lysozyme. The mode of action of this has not previously been investigated.

scholarly journals Isolation and Study of the Chemical Structure of a Disaccharide from Micrococcus lysodeikticus Cell Walls

1966 ◽  
Vol 241 (1) ◽  
pp. 223-230
Author(s):  
Nathan Sharon ◽  
Toshiaki Osawa ◽  
Harold M. Flowers ◽  
Roger W. Jeanloz
Keyword(s):  
Cell Walls ◽  
Chemical Structure ◽  
Micrococcus Lysodeikticus

scholarly journals Optimizing Chitin Depolymerization by Lysozyme to Long-Chain Oligosaccharides

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 320
Author(s):  
Arnaud Masselin ◽  
Antoine Rousseau ◽  
Stéphanie Pradeau ◽  
Laure Fort ◽  
Rodolphe Gueret ◽  
...  
Keyword(s):  
Time Course ◽  
Water Soluble ◽  
Organic Fertilizers ◽  
Symbiotic Associations ◽  
Egg White Lysozyme ◽  
Hen Egg White ◽  
Ecological Transition ◽  
Optimized Conditions ◽  
Hydrolysis Of ◽  
Long Chain

Chitin oligosaccharides (COs) hold high promise as organic fertilizers in the ongoing agro-ecological transition. Short- and long-chain COs can contribute to the establishment of symbiotic associations between plants and microorganisms, facilitating the uptake of soil nutrients by host plants. Long-chain COs trigger plant innate immunity. A fine investigation of these different signaling pathways requires improving the access to high-purity COs. Here, we used the response surface methodology to optimize the production of COs by enzymatic hydrolysis of water-soluble chitin (WSC) with hen egg-white lysozyme. The influence of WSC concentration, its acetylation degree, and the reaction time course were modelled using a Box–Behnken design. Under optimized conditions, water-soluble COs up to the nonasaccharide were formed in 51% yield and purified to homogeneity. This straightforward approach opens new avenues to determine the complex roles of COs in plants.

scholarly journals A Long Chain Terpenyl Pyrophosphate Synthetase from Micrococcus lysodeikticus

1967 ◽  
Vol 242 (8) ◽  
pp. 1895-1902 ◽  
Author(s):  
C.M. Allen ◽  
W. Alworth ◽  
A. Macrae ◽  
Konrad Bloch
Keyword(s):  
Micrococcus Lysodeikticus ◽  
Long Chain

THE HYDROLYSIS OF MONOPHOSPHOINOSITIDE BY EXTRACTS OF BRAIN

1967 ◽  
Vol 45 (6) ◽  
pp. 853-861 ◽  
Author(s):  
W. Thompson
Keyword(s):  
Fatty Acids ◽  
Enzyme Activity ◽  
Calcium Ions ◽  
Brain Extract ◽  
Monovalent Cations ◽  
High Concentration ◽  
Diffusible Factor ◽  
Hydrolysis Of ◽  
The Brain ◽  
Long Chain

The hydrolysis of monophosphoinositide by soluble extracts from rat brain is described. Diglyceride and inositol monophosphate are liberated along with a small amount of free fatty acids. Hydrolysis of the lipid is optimal at pH 5.4 in acetate buffer. The reaction is stimulated by calcium ions or by high concentration of monovalent cations and, to a less extent, by long-chain cationic amphipathic compounds. Enzyme activity is lost on dialysis of the brain extract and can be restored by diffusible factor(s). Some differences in the conditions for hydrolysis of mono- and tri-phosphoinositides are noted.

Effect of Modifiers on the Hydrolysis of Basic and Neutral Peptides by Carboxypeptidase B

1975 ◽  
Vol 53 (7) ◽  
pp. 747-757 ◽  
Author(s):  
Graham J. Moore ◽  
N. Leo Benoiton
Keyword(s):  
Active Site ◽  
Active Sites ◽  
Kinetic Behavior ◽  
Carboxypeptidase A ◽  
Phenyllactic Acid ◽  
Carboxypeptidase B ◽  
Substrate Complex ◽  
Enzyme Substrate ◽  
Basic Peptides ◽  
Hydrolysis Of

The initial rates of hydrolysis of Bz-Gly-Lys and Bz-Gly-Phe by carboxypeptidase B (CPB) are increased in the presence of the modifiers β-phenylpropionic acid, cyclohexanol, Bz-Gly, and Bz-Gly-Gly. The hydrolysis of the tripeptide Bz-Gly-Gly-Phe is also activated by Bz-Gly and Bz-Gly-Gly, but none of these modifiers activate the hydrolysis of Bz-Gly-Gly-Lys, Z-Leu-Ala-Phe, or Bz-Gly-phenyllactic acid by CPB. All modifiers except cyclohexanol display inhibitory modes of binding when present in high concentration.Examination of Lineweaver–Burk plots in the presence of fixed concentrations of Bz-Gly has shown that activation of the hydrolysis of neutral and basic peptides by CPB, as reflected in the values of the extrapolated parameters, Km(app) and keat, occurs by different mechanisms. For Bz-Gly-Gly-Phe, activation occurs because the enzyme–modifier complex has a higher affinity than the free enzyme for the substrate, whereas activation of the hydrolysis of Bz-Gly-Lys derives from an increase in the rate of breakdown of the enzyme–substrate complex to give products.Cyclohexanol differs from Bz-Gly and Bz-Gly-Gly in that it displays no inhibitory mode of binding with any of the substrates examined, activates only the hydrolysis of dipeptides by CPB, and has a greater effect on the hydrolysis of the basic dipeptide than on the neutral dipeptide. Moreover, when Bz-Gly-Lys is the substrate, cyclohexanol activates its hydrolysis by CPB by increasing both the enzyme–substrate binding affinity and the rate of the catalytic step, an effect different from that observed when Bz-Gly is the modifier.The anomalous kinetic behavior of CPB is remarkably similar to that of carboxypeptidase A, and is a good indication that both enzymes have very similar structures in and around their respective active sites. A binding site for activator molecules down the cleft of the active site is proposed for CPB to explain the observed kinetic behavior.

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