title: Nanosecond electric pulses deprive zinc ions of carboxypeptidase G2.
abstract: Nanosecond electric pulses (nsEP, 10kV/cm with a pulse duration of 8, 16 or 24ns) inhibited the activity of carboxypeptidase G2 (CPG2), a zinc-dependent homodimer; the relative activity was <20% when the total exposure time was >120s. No alterations were detected in electrophoresis, chromatography, mass spectroscopy and circular dichroism, thus demonstrating intactness of the apoenzyme. Inductively coupled plasma-mass spectrometry indicated that zinc levels were 3.30μg/mg protein in control CPG2, and decreased to 0.40, 0.12 or 0.38μg/mg protein after 240s of 8-, 16- or 24-ns pulses, respectively. In CPG2 exposed to 240s of 8-, 16- and 24-ns pulses, the reloading of zinc with redialysis recovered the activity to 94.7±3.4%, 84.0±5.2% and 81.7±7.0%, respectively (p=0.0853, 0.0741, 0.0668). These data demonstrated that nsEP inhibited CPG2 via removal of zinc, and that nsEP can be used to modulate CPG2.
authors.affiliation: Key Medical Laboratory of Obstetrics and Gynecology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010, China. Electronic address: yutinghe@hotmail.com.
authors.forename: Tinghe
authors.initials: T
authors.lastname: Yu
authors.affiliation: Key Medical Laboratory of Obstetrics and Gynecology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Fu
mesh_terms: D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004558:Electric Stimulation; D004591:Electrophoresis, Polyacrylamide Gel; D013058:Mass Spectrometry; D015032:Zinc / Q000737:chemistry*; D011623:gamma-Glutamyl Hydrolase / Q000737:chemistry* / Q000378:metabolism
chemical_list: D011623:gamma-Glutamyl Hydrolase; D015032:Zinc
keywords: Apoenzyme; Carboxypeptidase G2; Catalytic activity; Electric pulses; Zinc