The enzyme arginase catalyses the divalent cation dependent hydrolysis of L-arginine to produce L-ornithine and urea. Two isoforms of arginases have been identified in mammalian (including human) cells. Moreover, some infectious pathogens (e.g. Leishmania) synthesize their own arginase. Work over the last decades has revealed that elevated arginase activity both decreases cellular availability ...

L-arginine can be metabolized to nitric oxide (NO) by nitric oxide synthase (NOS) and to urea and L-ornithine by arginase. Competition between these pathways for L-arginine in inflammatory sites has been suggested. In experimental glomerulonephritis glomeruli produce nitrite; a major source is macrophages. We hypothesized that arginase is present in glomeruli and may compete for substrate with ...

Myeloid suppressor cells (MSCs) producing high levels of arginase I block T cell function by depleting l-arginine in cancer, chronic infections, and trauma patients. In cancer, MSCs infiltrating tumors and in circulation are an important mechanism for tumor evasion and impair the therapeutic potential of cancer immunotherapies. However, the mechanisms that induce arginase I in MSCs in cancer ar...

Arginase deficiency is caused by deficiency of arginase 1 (ARG1), a urea cycle enzyme that converts arginine to ornithine. Clinical features of arginase deficiency include elevated plasma arginine levels, spastic diplegia, intellectual disability, seizures and growth deficiency. Unlike other urea cycle disorders, recurrent hyperammonemia is typically less severe in this disorder. Normalization ...

Physiocochemical properties of beef liver arginase are reported, particular attention being given to its state of aggregation in the concentration range encountered in enzymic assays. It is shown that a species of molecular weight 114,000 is the operational kinetic unit. Evidence is also provided that arginase does not associate heterogeneously with urease, and therefore, in the absence of macr...

Caesalpinia sappan (C. sappan) is a medicinal plant used for promoting blood circulation and removing stasis. During a screening procedure on medicinal plants, the ethylacetate extract of the lignum of C. sappan (CLE) showed inhibitory activity on arginase which has recently been reported as a novel therapeutic target for the treatment of cardiovascular diseases such as atherosclerosis. CLE inh...

l-Arginine can be metabolized by nitric oxide (NO) synthase (NOS) to produce NO or by arginase to produce urea andl-ornithine. In the liver, arginase (the AI isoform) is a key enzyme in the urea cycle. In extrahepatic organs including the lung, the function of arginase (the AII isoform) is less clear. Because we found that lung AII was upregulated during 100% O2exposure in preliminary experimen...

Since both increased nitric oxide (NO) synthase (NOS) abundance and diminished NO signaling have been reported in the aging penis, the role of NO in the adaptations of aging remains controversial. Here we tested the hypothesis that arginase, an enzyme that competes with NOS for the substrate l-arginine, contributes to erectile dysfunction with advanced age in the B6/129 mouse strain. Arginase p...

Emerging evidence supports the idea that arginase, expressed in the vascular endothelial cells of humans and other species, modulates endothelial nitric oxide (NO) synthase-3 (NOS-3) activity by regulating intracellular L-arginine bioavailability. Arginase II is thought to be expressed in the mitochondria of a variety of nonendothelial cells, whereas arginase I is known to be confined to the cy...

L-Arginine is the common substrate for two enzymes, arginase and nitric oxide synthase (NOS). Arginase converts L-arginine to L-ornithine, which is the precursor of polyamines, which are essential components of cell proliferation. NOS converts L-arginine to produce NO, which inhibits proliferation of many cell lines. Various human breast cancer cell lines were initially screened for the presenc...