The measurement of lysozyme activity and the ultra-violet inactivation of lysozyme

Shugar, David

doi:10.1016/0006-3002(52)90045-0

Cited by 1,070 publications

(445 citation statements)

References 10 publications

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“…Cell lysate (CL) was stored at -20°C until used. Lysozyme concentration was determined spectrophotometrically according to the method of Shugar (1952). Samples (50 p1 SN or CL) were added to 1 m1 of a bacterial suspension (lyophilized Micrococcus lysodeikticus, 20 mg m1 ' in 66 mM phosphate buffer at pH 5.5) and turbimetric changes were recorded for 100 S at 450 nm (Secoman, S1000 spectrophotometer).…”

Section: Methodsmentioning

confidence: 99%

Defense factors in clam extrapallial fluids

Allam¹,

Paillard²

1998

Dis. Aquat. Org.

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The extrapallial fluid of clams is located between the external epithelium of the mantle and the Inner face of the shell. The pallial line separates the fluid into central and peripheral extrapallial fluids (CEF and PEF, respectively). These fluids are the sites of biomineralization, but th(,ir role in other biological processes, such as defense, remains unknown. A comparative study of some characteristics of the cellular and humoral fractions of the extrapallial fluids and hemolymph of the Manila clam Ruditapesphilippinarum was carried out. Both CEF and PEF contained abundant hemocytes cornparable to those found in hemolymph. Total and viable hemocyte counts were high especially In the CEF. Extrapallial fluid cell lysate and supernatant showed significant bacteriolytic (lysozyme-like) activity. The CEF was found to be bacteriologically sterile. This sterility may result from the presence in the CEF of significant defense factors in the form of numerous macrophage-like cells and high lysozyme activity. These findings are of interest in the case of bivalves susceptible to shell diseases such as R. philippinarum, which is suscept~ble to a bacterial disease caused by Vibrio tapetis.

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Section: Methodsmentioning

confidence: 99%

Defense factors in clam extrapallial fluids

Allam¹,

Paillard²

1998

Dis. Aquat. Org.

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“…The fully associated complex does exhibit about 5% of WT activity in the Micrococcus luteus cell wall assay (Shugar, 1952). This residual activity was usually ignored in the analysis, but inclusion sometimes improved the fit of the data to the calculated curves generated by the models (Equation 2 of Rajpal et al, 1998).…”

Section: Methodsmentioning

confidence: 99%

“…Aliquots of lysozyme (10 nM = 100 X ICD) were pre-incubated at 25 "C for 1 h with various volumes of added antibody stock solution, and the residual activity monitored by the M. luteus assay (Shugar, 1952). The concentration of antibody was determined by extrapolating the volume of added antibody stock solution necessary to effect maximal inhibition of lysozyme activity.…”

Section: Determination Of Antibody Concentrationmentioning

confidence: 99%

Kinetic epitope mapping of the chicken lysozyme.HyHEL‐10 fab complex: Delineation of docking trajectories

1998

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“…The specific bacteriolytic activities of lysozyme variants were measured spectrophotometrically by a modification of the turbidity assay of Shugar (1952) as described by Shih et al (1993). Enzyme concentrations that gave ca.…”

Section: Activity Assaymentioning

confidence: 99%

Thermal stability determinants of chicken egg‐white lysozyme core mutants: Hydrophobicity, packing volume, and conserved buried water molecules

1995

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A series of 24 mutants was made in the buried core of chicken lysozyme at positions 40, 5 5 , and 91. The midpoint temperature of thermal denaturation transition (T,) values of these core constructs range from 60.9 to 77.3 "C, extending an earlier, more limited investigation on thermostability. The T,,, values of variants containing conservative replacements for the wild type (WT) (Thr 40-Ile 55-Ser 91) triplet are linearly correlated with hydrophobicity (r = 0.81) and, to a lesser degree, with combined side-chain volume (r = 0.75). The X-ray structures of the S91A (1.9A) and 155L/S91T/DlOlS (1.7 A) mutants are presented. The former amino acid change is found in duck and mammalian lysozymes, and the latter contains the most thermostable core triplet. A network of four conserved, buried water molecules is associated with the core. It is postulated that these water molecules significantly influence the mutational tolerance at the individual triplet positions. The pH dependence of T, for the S91D mutant was compared with that of WT enzyme. The pK, of S91D is 1.2 units higher in the native than in the denatured state, corresponding to AAG298 = 1.7 kcal/mol. This is a low value for charge burial and likely reflects the moderating influence of the buried water molecules or a conformational change. Thermal and chemical denaturation and far UV CD spectroscopy were used to characterize the in vitro properties of I55T. This variant, which buries a hydroxyl group, has similar properties to those of the human amyloidogenic variant I56T.

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The measurement of lysozyme activity and the ultra-violet inactivation of lysozyme

Cited by 1,070 publications

References 10 publications

Defense factors in clam extrapallial fluids

Defense factors in clam extrapallial fluids

Kinetic epitope mapping of the chicken lysozyme.HyHEL‐10 fab complex: Delineation of docking trajectories

Thermal stability determinants of chicken egg‐white lysozyme core mutants: Hydrophobicity, packing volume, and conserved buried water molecules

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