Horseradish peroxidase (HRP) catalyzes the oxidative chemiluminescent reaction of luminol, and firefly luciferase catalyzes the oxidation of firefly D-luciferin. Here we report a novel substrate, 5-(5'-azoluciferinyl)-2,3-dihydro-1,4-phthalazinedione (ALPDO), that can trigger the activity of HRP and firefly luciferase in solution because it contains both luminol and luciferin functionalities. I...

Previously reported rates of reaction between six mutant strains of the enzyme horseradish peroxidase (HRP) and a test substrate, 2-methoxyphenol, were found to correlate with characteristic binding distances computed using molecular simulation. The correlation (R(2) = 0.86) bears out a working hypothesis that, based on a quantitative structure-activity relationship (QSAR) we had previously dev...

The (pro)renin receptor [(P)RR], a new component the renin-angiotensin system, was cloned recently. The (P)RR promotes direct mitogen-activated protein kinase signaling and nonproteolytic prorenin activation. We investigated the role of a (P)RR blocker, a peptide consisting of 10 amino acids from the prorenin prosegment called the "handle-region" peptide (HRP), on target organ damage in renovas...

A synthetic gene encoding horseradish peroxidase isoenzyme C (HRP C) has been synthesized and expressed in Escherichia coli. The nonglycosylated recombinant enzyme (HRP C*) was produced in inclusion bodies in an insoluble inactive form containing only traces of heme. HRP C* was solubilized and conditions under which it folded to give active enzyme were determined. Folding was shown to be critic...

DNA methylation catalyzed by methyltransferase (MTase) is a significant epigenetic process for modulating gene expression. Traditional methods to study MTase activity require a laborious and costly DNA labeling process. In this article, we report a simple, colorimetric, and label-free methylation-responsive DNAzyme (MR-DNAzyme) strategy for MTase activity analysis. This new strategy relies on h...

Horseradish peroxidase (HRP), conjugated to antibodies and lectins, is widely used in medical diagnostics. Since recombinant production of the enzyme is difficult, HRP isolated from plant is used for these applications. Production in the yeast Pichia pastoris (P. pastoris), the most promising recombinant production platform to date, causes hyperglycosylation of HRP, which in turn complicates co...

In parotid acinar cells, horseradish peroxidase (HRP) administered via the main excretory duct is endocytosed from the apical cell surface in smooth C- or ring-shaped vesicles (Oliver, C. and A. R. Hand. 1979. J. Cell Biol. 76:207). These vesicles ultimately fuse with lysosomes adjacent to the Golgi apparatus. The present investigation extends these findings and examines the uptake and fate of ...

The in vitro interaction of soluble horseradish peroxidase (HRP) with homogeneous mono layers of mouse macrophages has been studied using sensitive biochemical and cytochemical techniques. The compartmentalization of HRP in extracellular and intracellular sites has been quantitatively evaluated. A significant fraction is bound to a serum-derived layer, which coats the surface of culture vessels...

Visualization of the neuronal tract tracer horseradish peroxidase (HRP) is commonly achieved through the histochemical detection of its enzymatic activity using 3,3',5,5'-tetramethylbenzidine (TMB) as a chromogen. However, the TMB product is unstable and is incompatible with tissue processing methods that render the enzyme inactive, or when a combination of HRP tract tracing with neuronal pheno...

The Hrp (type III protein secretion) system is essential for the plant parasitic ability of Pseudomonas syringae and most Gram-negative bacterial plant pathogens. AvrB and AvrPto are two P. syringae proteins that have biological activity when produced via heterologous gene expression inside plant cells or when produced by Hrp+ bacteria. Avr-like proteins, presumably injected by the Hrp system o...