ISSN:
1574-6968
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Abstract An atypical Citrobacter sp. isolated from a heavy metal-polluted site has a PhoN-type acid phosphatase that is responsible for the precipitation of heavy metals as cell-bound metal phosphates via liberated inorganic phosphate, supplied via enzymic cleavage of a phosphomonoester substrate. Phosphatase activity, comprising two isoenzymes designated CPI and CPII, was resistant to cadmium (II), zinc (II) and lead (II), but sensitive to uranyl and vanadyl oxycations and cupric ion. The monovalent cations of mercury (I) and silver (I), and trivalent yttrium (III) were inhibitory, particularly to CPII. Theanionic counterion did not influence metal toxicity. The Km of CPII towards some phosphomonoester substrates was higher than than that of CPI, suggesting that although the two isoenzymes were shown previously to be closely related, subtle differences exist between them that justify their classification as separate isoenzymes, for which the physiological function is still obscure.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1574-6968.1995.tb07722.x
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