Catalyzes the specific dephosphorylation of phosphoarginine residues in a large number of proteins. Counteracts the protein arginine kinase McsB in vivo. Can dephosphorylate CtsR-P; thus, can restore the DNA-binding ability of the CtsR repressor by reversing the McsB-mediated phosphorylation. Is the only active pArg phosphatase present in B.subtilis. Exhibits almost no activity against pSer, pThr, or pTyr peptides. Appears to play a role in B.subtilis stress resistance. Protein arginine phosphorylation has a physiologically important role and is involved in the regulation of many critical cellular processes, such as protein homeostasis, motility, competence, and stringent and stress responses, by regulating gene expression and protein activity. H2O + N(omega)-phospho-L-arginyl-[protein] = L-arginyl-[protein] + phosphate Efficiently inhibited by Cu(2+) ion, Zn(2+) ion, sodium pyrophosphate and N-ethylmaleimide, while the addition of Mg(2+), Ca(2+) or Fe(3+) ions has minimal effect. Inhibited in a competitive manner by vanadate. kcat is 0.010 sec(-1) with pNPP as substrate (at 37 degrees Celsius and pH 5.5) (PubMed:15995210). kcat is 0.13 sec(-1) with pNPP as substrate (at 40 degrees Celsius and pH 8.0) (PubMed:23770242). pNPP is a phospho-tyrosine mimicking compound. Optimum pH is 5.5 with pNPP as substrate. Expression is up-regulated in the exponential phase of growth, followed by a significant and gradual reduction in the stationary/sporulation phase. Is not up-regulated during ethanol stress. Cellular protein arginine phosphorylation is only detectable in a ywlE mutant and not in the wild-type strain, and global gene expression is significantly impacted in the mutant strain (PubMed:22517742 and PubMed:24263382). Cells lacking this gene are impaired in dephosphorylating McsB-P (PubMed:23770242). They also show a reduced resistance to ethanol stress (PubMed:15995210). Belongs to the low molecular weight phosphotyrosine protein phosphatase family. Was originally thought to be a protein-tyrosine-phosphatase (PubMed:15995210). Was later shown to function as an arginine phosphatase in vivo and in vitro (PubMed:22517742 and PubMed:23770242).