We investigated expression of acid phosphatases containing low-molecular-mass (25 to 27-ma) polypeptides (Lmmp-APs) similar to those described previously for Salmonella enterica serovar typhimurium and Morganella morganii in strains that were representatives of 43 different enterobacterial species by using a zymogram technique developed for detection of Lmmp-AP activities and for analysis of some of the properties of these enzymes. Under conditions that were suitable for detection of the previously described Lmmp-APs, production of similar enzymes appeared to be widespread but not universal among enteric bacteria, and heterogeneous patterns of expression were found among strains belonging to different genera and, in some cases, among strains belonging to different species of the same genus. We found that class A Lmmp-APs (i.e., Lmmp-Aps similar to the Morganella morganii PhoC and Salmonella enterica serovar typhimurium PhoN acid phosphatases) were also expressed in Cedecea spp., Enterobacter aerogenes, Hafiia alvei, Klebsiella spp., Providencia stuartii, Serratia plymuthica, and Yokenella regensburgei strains and that class B Lmmp-APs (i.e., Lmmp-APs similar to the Morganella morganii NapA and Salmonella enterica serovar typhimurium NapII acid phosphatases) were also expressed in strains of Citrobacter spp., Escherichia coli, Escherichia fergusonii, H a f i b alvei, Proteus mirabilis, Providenciu spp., Salmonella enterica serovar typhi, ShigeUa dysenteriae, and ShigeUa flexneri. No Lmmp-AP activity was detected in strains of Enterobacter spp. other than Enterobacter aerogenes, Escherichia hermanii, Kluyvera ascorbata, Leckrciu adecarboxyluta, Leminorella grimontii, MoellereUa wisconsensis, Proteus vulgaris, Proteus penneri, Serratia spp. other than Serratia plymuthica, and Yersinia spp. Because of the heterogeneous patterns of expression of Lmmp-APs, analysis of these enzymes could be useful for evolutionary studies of the enterobacterial genome and for precise phylogenetic positioning of enteric bacteria.Phosphatase activity occurs in all members of the family Enterobacteriaceae (18), but different patterns of phosphatase activity have been found in strains belonging to this family (2, 3, 10, 12, 13, 19). For instance, it is known that a phosphaterepressible alkaline phosphatase is widespread but not universally present in enterobacterial species (2, 13, 19). It is also known that the levels of cyclic phosphodiesterase activity and 5'-nucleotidase (UDP-sugar hydrolase) activity can be markedly different in different species (10) and that two different types of 5'-nucleotidases are produced by Escherichia coli and Salmonella spp. as a consequence of alternative silencing events in the genes that encode these enzymes (3). Moreover, only some species (Morganella morganii and Providencia stuartii) produce high levels of phosphate-irrepressible acid phosphatase activity (HPAP phenotype), while other species produce only intermediate or low levels of acid phosphatase activity when Pi is freely available in the cultu...

The olpA gene of Chryseobacterium meningosepticum, encoding a molecular class C phosphatase, was cloned and expressed in Escherichia coli. The gene encodes a 29-kDa polypeptide containing an amino-terminal signal peptide typical of bacterial membrane lipoproteins. Expression in E. coli results in a functional product that mostly partitions in the outer membrane. A secreted soluble OlpA derivative (sOlpA) lacking the N-terminal cysteine residue for lipid anchoring was produced in E. coli and purified by means of two steps of ion exchange chromatography. Analysis of the kinetic parameters of sOlpA with several organic phosphoesters revealed that the enzyme was able to efficiently hydrolyze nucleotide monophosphates, with a strong preference for 5V -nucleotides and for 3V -AMP. The enzyme was also able to hydrolyze sugar phosphates and h-glycerol phosphate, although with a lower efficiency, whereas it was apparently inactive against nucleotide di-and triphosphates, diesters, and phytate. OlpA, therefore, can be considered a broad-spectrum nucleotidase with preference for 5V -nucleotides. Its functional behaviour exhibits differences from that of the Haemophilus influenzae OMP P4 lipoprotein, revealing functional heterogeneity among phosphatases of molecular class C. D