Catalase plays a key role as an antioxidant, protecting aerobic organisms from the toxic effects of hydrogen peroxide, and in some cases has been postulated to be a virulence factor. To help elucidate the function of catalase in Candida albicans, a single C. albicans-derived catalase gene, designated CAT1, was isolated and cloned. Degenerate PCR primers based on highly conserved areas of other ...

We previously identified several members of the SLC7 transporter family as potential system c transporters based on immunofluorescence data and, for functionally characterized members, on cysteamine-cysteine competition experiments. CAT2A, CAT2B, an orphan CAT-like protein named SLC7A14 and, to a lesser extent, CAT1 appeared as good system c candidates. However, it is still unknown which of the...

The CSRE (carbon source-responsive element) is a sequence motif responsible for the transcriptional activation of gluconeogenic structural genes in Saccharomyces cerevisiae. We have isolated a regulatory gene, DIL1 (derepression of isocitrate lyase, = CAT8), which is specifically required for derepression of CSRE-dependent genes. Expression of CAT8 is carbon source regulated and requires a func...

Previous work from our laboratory has demonstrated that the inner medullary collecting duct (IMCD) expresses a large amount of nitric oxide synthase (NOS) activity. The present study was designed to characterize the transport of NOS substrate, L-arginine, in a suspension of bulk-isolated IMCD cells from the Sprague-Dawley rat kidney. Biochemical transport studies demonstrated an L-arginine tran...

Reactive oxygen species (ROS), including hydrogen peroxide (H(2)O(2)), are among the important second messengers in abscisic acid (ABA) signaling in guard cells. In this study, to investigate specific roles of H(2)O(2) in ABA signaling in guard cells, we examined the effects of mutations in the guard cell-expressed catalase (CAT) genes, CAT1 and CAT3, and of the CAT inhibitor 3-aminotriazole (A...

NO synthase (NOS) enzymes convert L-arginine to NO in two sequential reactions whose rates (k(cat1) and k(cat2)) are both limited by the rate of ferric heme reduction (k(r)). An enzyme ferric heme-NO complex forms as an immediate product complex and then undergoes either dissociation (at a rate that we denote as k(d)) to release NO in a productive manner, or reduction (k(r)) to form a ferrous h...