Heat inactivation was studied at 45, 50, 55, and 60 degrees for all of the phenyl valerate hydrolases (PVase), including neurotoxic esterase (NTE) and inhibitor-resistant esterase (IRE), in homogenates of hen or rat brain or in preparations of hen brain microsomal membranes. Hen and rat brain homogenates were prepared in buffer (50 mM Tris/0.20 mM EDTA, pH 8.00, at 25 degrees). Hen brain micros...

Low pH and salt are two factors contributing to the inactivation of bacterial pathogens during a 60-day curing period for cheese. The kinetics of inactivation for Mycobacterium avium subsp. paratuberculosis strains ATCC 19698 and Dominic were measured at 20 degrees C under different pH and NaCl conditions commonly used in processing cheese. The corresponding D values (decimal reduction times; t...

In a previous paper (1) the inactivation of catalase by heat at different pH was studied. It was discovered that the heat inactivation depends upon the hydrogen ion concentration of the enzyme solution which affects both the velocity and the extent of the reaction. It was also found there that 65” was the critical temperature for the enzyme preparation since at this temperature the catalase was...

We evaluated analytic performances of an automated treponemal test and compared this test with the Venereal Disease Research Laboratory test (VDRL) and fluorescent treponemal antibody absorption test (FTA-ABS). Precision performance of the Architect Syphilis TP assay (TP; Abbott Japan, Tokyo, Japan) was assessed, and 150 serum samples were assayed with the TP before and after heat inactivation ...

BACKGROUND Prions, infectious agents associated with transmissible spongiform encephalopathy, are primarily composed of the misfolded and pathogenic form (PrPSc) of the host-encoded prion protein. Because PrPSc retains infectivity after undergoing routine sterilizing processes, the cause of bovine spongiform encephalopathy (BSE) outbreaks are suspected to be feeding cattle meat and bone meals (...

The enzyme histidine ammonia-lyase (histidase) is required for growth of Streptomyces griseus on L-histidine as the sole source of nitrogen. Histidase was induced by the inclusion of histidine in the medium, regardless of the presence of other carbon and nitrogen sources. Histidase activity was increased by a shift of culture incubation temperature from 30 to 37 degrees C. Conversely, upon indu...

Ab s t r a c t . The thermal degradation of Aspergillus oryzae α-amylase in the presence of sugars (sucrose, trehalose) and polyols (sorbitol, glycerol) as stabilization additives was investigated. The aim of the study was to test whether it is possible to estimate the heat stability of the enzyme based on the amount of hydroxyl groups provided in a buffer solution from different sources. The t...

In a previous paper (1) the inactivation of catalase by heat at different pH was studied. It was discovered that the heat inactivation depends upon the hydrogen ion concentration of the enzyme solution which affects both the velocity and the extent of the reaction. It was also found there that 65” was the critical temperature for the enzyme preparation since at this temperature the catalase was...

Abstraet--N-Acetyl-hexosaminidase (Hex) exists in various human tissues in two major isozymic forms--Hex A and Hex B. The main difference between the two forms is the lability of Hex A to both heat and acid as compared to the stability of Hex B. When heated to 50°C for 2-3 hr Hex A loses its entire enzymatic activity. In the present study we demonstrate that specific antiserum stabilizes Hex A ...

In a previous paper (1) the inactivation of catalase by heat at different pH was studied. It was discovered that the heat inactivation depends upon the hydrogen ion concentration of the enzyme solution which affects both the velocity and the extent of the reaction. It was also found there that 65” was the critical temperature for the enzyme preparation since at this temperature the catalase was...