DNase, containing 3 tryptophan residues, can be inactivated by modification of this amino acid with Nbromosuccinimide. Chromatography of acid hydrolysates shows all three tryptophan residues modified by the time inactivation is complete. However, spectrophotometric measurement indicates that only 2 residues are modified. The discrepancy is due to the unreliability of the spectrophotometric meth...

The object of this study was to define minimized biotin-binding fragments, or 'prorecognition sites', of either the egg-white glycoprotein avidin or its bacterial analogue streptavidin. Because of the extreme stability to enzymic hydrolysis, fragments of avidin were prepared by chemical means and examined for their individual biotin-binding capacity. Treatment of avidin with hydroxylamine was s...

Arthrobacter sialophilus neuraminidase catalyzes the hydrolysis of N-acetylneuraminyl-alpha-oxygen, nitrogen, and azido glycosides. The most effective of those substrates examined was N-acetylneuraminyl-alpha-4-methylumbelliferylglycoside (AcNeu-alpha-4-MU; Km app, 0.0193 mM; kcat, 136.4 sec-1). The products resulting from the enzymic hydrolysis of N-acetylneuraminyl-alpha-azido-glycoside were ...

The hydrolysis of Whatman no. 1 filter paper by purified cellulolytic components from Trichoderma reesei and the synergistic action of binary combinations of these enzymes on the same substrate were investigated. At 20 milligrams filter paper, enzyme concentrations needed to obtain half-maximal hydrolysis rates (KE values) were in the 3-4 microM range for the cellobiohydrolases (CBHs) and 0.05-...

1. Biosynthetic sodium (N-acetyl-N-phenylhydroxylamine NO-f-D-glucosid)uronate is hydrolysed completely by purified mouse urinary fl-glucuronidase into the products N-acetyl-N-phenylhydroxylamine and glucuronic acid. The hydrolysis is inhibited by saccharo-(1 -*4)-lactone. These results not only confirm the identity and purity of the substrate but also establish it as a substrate for :-glucuron...

PLAWALOGENS are a group of aldehydogenic substances widely distributed in nature in both the animal and plant kingdom. 4 Their chemical structure is that of a c&l(alk-l’enyl) ether of a 2-acyl-3glycerylphosphate (I) where R” may be derived from choline, ethanolamine or serine. Hydrogenation and acid hydrolysis8 yielded chimyl and batyl alcohols (IIa and IIb), while enzymic hydrolysis followed b...

more toxic by intraperitoneal injection than any of the simple peroxides with which it was compared. Autoxidized methyl linoleate was less toxic than most of the simple peroxides. 5. The LD50 of autoxidized linoleic acid (0.26 ,mole of peroxide/g.) was only slightly higher than the mean increase of peroxide previously found in mice after 950r. of X-rays (0.22 lamole/g.). 6. Injected peroxides k...