DOES TRYPSIN INACTIVATE UREASE?

Does trypsin cut before proline?

Trypsin is the most commonly used enzyme in mass spectrometry for protein digestion with high substrate specificity. Many peptide identification algorithms incorporate these specificity rules as filtering criteria. A generally accepted "Keil rule" is that trypsin cleaves next to arginine or lysine, but not before proline. Since this rule was derived two decades ago based on a small number of ex...

Superoxide and peroxynitrite inactivate aconitases, but nitric oxide does not.

The Escherichia coli and recombinant human cytosolic aconitases are inactivated by O2-., with a rate constant of approximately 3 x 10(7) M-1 s-1; the corresponding value for the porcine mitochondrial aconitase is approximately 0.8 x 10(7) M-1 s-1. Nitric oxide, which is reported to inactivate aconitase, did not do so at a perceptible rate, while incubation with peroxynitrite led to a rapid loss...

Heat inactivation of trypsin inhibitor, lipoxygenase and urease in soybeans: effect of acid and base additives.

Site-directed mutation of conserved cysteine residues does not inactivate the Streptococcus pyogenes hyaluronan synthase.

Hyaluronan synthase (HAS), the enzyme responsible for the production of hyaluronic acid (HA), is a well-conserved membrane-bound protein in both prokaryotes and eukaryotes. This enzyme performs at least six discrete functions in producing a heterodisaccharide polymer of several million molecular weight and extruding it from the cell. Among the conserved motifs and domains within the Class I HAS...

Pseudomonas aeruginosa elastase does not inactivate alpha 1-proteinase inhibitor in the presence of leukocyte elastase.

Pseudomonas aeruginosa elastase rapidly inactivates alpha 1-proteinase inhibitor by splitting its Pro-357-Met-358 peptide bond. The present study was aimed at testing whether this reaction takes place in the presence of leukocyte elastase. To this end was added alpha 1-proteinase inhibitor to a mixture of the two elastases, and we performed the following assays: (i) measurement of the residual ...