Muramidase

Fi re 3.9 Schematic diagram of the structure of one domain of a bacterial muramidase, comprising 450 amino acid residues. The structure is built up from 27 a helices arranged in a two-layered ring. The ring has a large central hole, like a doughnut, with a diameter of about 30 A. 

Thunissen, A.-M., et al. Doughnut-shaped stmcture of a bacterial muramidase revealed by x-ray crystallography. Nature 367 750-753, 1994. 

J. E. Churchich, Luminescence properties of muramidase and reoxidized muramidase,... 

This enzyme [EC 3.2.1.17], also called muramidase, catalyzes the hydrolysis of the l,4-/3-linkages between N-acetyl-D-glucosamine and A-acetylmuramic acid in pep-tidoglycan heteropolymers of prokaryotic cell walls. Some chitinases [EC 3.2.1.14] also exhibit this activity. See Kinetic Isotope Effect... 

Enzymes activities are particularly sensitive to the anticoagulant used in collecting the specimen. Heparin inhibits acid phosphatase (W16) and muramidase (Z5). Amylase activity is inhibited by oxalate or citrate (MIO), and lactic dehydrogenase and acid phosphatase lose activity in oxalate (C2). Alkaline phosphatase is stable in oxalate, oxalate-fluoride, or heparin, but 25 mAf citrate inhibits 50% of the activity, and as little as 50 mlf EDTA is completely inhibitory (B19). Leucine aminopeptidase is inhibited by EDTA, as is creatine phosphokinase (F3). Amylase activity has been reported to be only 83% of that in serum when oxalate or citrate-plasma is used (MIO). Heparin plasma appears to have no inhibitory effect. Despite the fact that clotting factor V is not stable in oxalate or EDTA, these are often used as anticoagulants to obtain plasma for prothrombin determinations (Z2, Z4). 

Z5. Zucker, S., and Webb, A. M., Assay of muramidase activity in serum, plasma, or urine. Stand. Methods Clin. Chem. 7, 9-17 (1972). 

Lysozyme (muramidase, mucopeptide JV-acetylmuramylhydrolase) is a widely distributed enzyme which lyses certain bacteria by hydrolysing the / (l-4)-linkage between muramic acid and N-acetylglucosamine of mucopolysaccharides of the bacterial cell wall. 

Analytical enzymes, such as glucose oxidase, galactose oxidase, alcohol dehydrogenase, hexokinase, muramidase, and cholesterol oxidase... 

Lysozyme (Muramidase, /V-acetylmuramyl hydrolase, iV-acetylmuramide, peptidoglycan N-acetylmuramoyl hydrolase. Globulin G ) [human 174883-18-2, from human neutrophils 9001-63-2, from human milk 12671-19-1, from chicken egg white 126050-88-3, chloride from chicken egg white 9066-59-... 

The muramidasic activity of an unknown lysozyme sample is determined by comparing the initial lysis rate of a M. luteus suspension expressed in absorbance decrease per minute at 450 nm with the lysis rate of the same substrate suspension caused by the lysozyme HC1 F.I.P. standard in the same conditions. 

Citter cells/ xanthogranuloma Crowded macrophages engorged with lipid vacuoles eccentric nucleus noncohesive cells a-ACT (S) KP1 (-I-) muramidase (S) CNS... 

Lysozyme or muramidase, is an enzyme that catalyses the hydrolysis of the peptidoglycan layer of bacterial cell walls. The urinary excretion of lysozyme increases during urinary tract infections, proximal tubular damage, and excessive endogenous lysozyme synthesis that overwhelm the absorption capacity of the proximal tubule. 

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