[Polyphenolic antioxidants efficiently protect urease from inactivation by ultrasonic cavitation].
Inactivation of urease (25 nM) in aqueous solutions (pH 5.0-6.0) treated with low-frequency ultrasound (LFUS; 27 kHz, 60 Wt/cm2, 36-56 degrees C) or high-frequency ultrasound (HFUS; 2.64 MHz, 1 Wt/cm2, 36 or 56 degrees C) has been characterized quantitatively, using first-order rate constants: kin, aggregate inactivation; kin*, thermal inactivation; and kin* (US), ultrasonic inactivation. Within the range from 1 nM to 10 microM, propyl gallate (PG) decreases approximately threefold the rate of LFUS-induced inactivation of urease (56 degrees C), whereas resorcinol poly-2-disulfide prevents this process at 1 nM or higher concentrations. PG completely inhibits HFUS-induced inactivation of urease at 1 nM (36 degrees C) or 10 nM (56 degrees C). At 0.2-10 microM, human serum albumin (HSA) increases the resistance of urease (at 56 degrees C) treated with HFUS to temperature- and cavitation-induced inactivation. Complexes of gallic acid polydisulfide (GAPDS) with HSA (GAPDS-HSA), formed by conjugation of 1.0 nM PGDS with 0.33 nM HSA, prevent HFUS-induced urease inactivation (56 degrees C).
Metelitsa
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DI
Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Minsk, 220141 Belarus. metelitza@iboch.bas-net.by
Tarun
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EI
Losev
Iu P
IuP
D000975:Antioxidants / Q000494:pharmacology*; D004220:Disulfides / Q000737:chemistry; D004789:Enzyme Activation / Q000187:drug effects; D007700:Kinetics; D011435:Propyl Gallate / Q000494:pharmacology; D012118:Resorcinols / Q000737:chemistry / Q000494:pharmacology; D012709:Serum Albumin / Q000737:chemistry / Q000494:pharmacology; D012996:Solutions; D013696:Temperature; D014465:Ultrasonics; D014510:Urease / Q000737:chemistry*; D014867:Water
D000975:Antioxidants; D004220:Disulfides; D012118:Resorcinols; D012709:Serum Albumin; D012996:Solutions; D014867:Water; D011435:Propyl Gallate; D014510:Urease