Some organophosphorus compounds are toxic because they inhibit acetylcholinesterase (AChE) by phosphylation of the active site serine, forming a stable conjugate: Ser-O-P(O)-(Y)-(XR) (where X can be O, N, or S and Y can be methyl, OR, or SR). The inhibited enzyme can undergo an aging process, during which the X-R moiety is dealkylated by breaking either the P-X or the X-R bond depending on the ...

Human paraoxonase 1 (PON1) has been portrayed as a catalytic bioscavenger which can hydrolyze large amounts of chemical warfare nerve agents (CWNAs) and organophosphate (OP) pesticides compared to the stoichiometric bioscavengers such as butyrylcholinesterase. We evaluated the protective efficacy of purified human and rabbit serum PON1 against nerve agents sarin and soman in guinea pigs. Cataly...

Organophosphorus nerve agents interfere with cholinergic signaling by covalently binding to the active site of the enzyme acetylcholinesterase (AChE). This inhibition causes an accumulation of the neurotransmitter acetylcholine, potentially leading to overstimulation of the nervous system and death. Current treatments include the use of antidotes that promote the release of functional AChE by a...

The nerve agents are chemical warfare agents known to be used during terrorist attacks. An inexpensive and portable system to be used by first responders and military personnel is of interest owing to the continuing threat of possible terrorist attacks. Amperometric biosensors based on cholinesterase inhibition show such potentialities. In this work butyrylcholinesterase was immobilized onto sc...

Organophosphorus (OP) nerve agents such as (S)-sarin are among the most highly toxic compounds that have been synthesized. Engineering enzymes that catalyze the hydrolysis of nerve agents ("bioscavengers") is an emerging prophylactic approach to diminish their toxic effects. Although its native function is not known, diisopropyl fluorophosphatase (DFPase) from Loligo vulgaris catalyzes the hydr...

672 Science Budget: Selective Growth a Science and the Domestic Spending Squeeze A Civilian R&D: The Big Four Federal Spenders 676 Where Have All Japan's Scientists Gone? 677 Sequencing Venture Sparks Alarm 678 Third World: S(ave) O(ur) S(heep)! 679 Stepping Up the Pressure On Indirect Costs 680 Briefings: Zagury in the Clear a Debut for 425-Million-Year-Old Fossil a Sarin Indicted a Neuro Nerv...

In the wake of the 11 September 2001 terrorist attacks on New York City and Washington, D.C., the threat posed by chemical and biological weapons has instantaneously evolved from hypothetical nightmare to clear and present danger. Under this new set of circumstances, any addition to the body of scientific knowledge about the health effects of chemical or biological agents is particularly timely...