title: A biochemical logic gate using an enzyme and its inhibitor. Part II: The logic gate.
abstract: Enzyme-Based Logic Gates (ENLOGs) are key components in bio-molecular systems for information processing. This report and the previous one in this series address the characterization of two bio-molecular switching elements, namely the alpha-chymotrypsin (alphaCT) derivative p-phenylazobenzoyl-alpha-chymotrypsin (PABalphaCT) and its inhibitor (proflavine), as well as their assembly into a logic gate. The experimental output of the proposed system is expressed in terms of enzymic activity and this was translated into logic output (i.e. "1" or "0") relative to a predetermined threshold value. We have found that an univalent link exists between the dominant isomers of PABalphaCT (cis or trans), the dominant form of either acridine (proflavine) or acridan and the logic output of the system. Thus, of all possible combinations, only the trans-PABalphaCT and the acridan lead to an enzymic activity that can be defined as logic output "1". The system operates under the rules of Boolean algebra and performs as an "AND" logic gate.
authors.affiliation: Department of Biomedical Engineering, Technion-Israel Institute of Technology, The Leonard and Diane Sherman Center for Research in Biomaterials, Haifa 32000, Israel.
authors.forename: Sarit
authors.initials: S
authors.lastname: Sivan
authors.forename: Samuel
authors.initials: S
authors.lastname: Tuchman
authors.forename: Noah
authors.initials: N
authors.lastname: Lotan
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods; D002918:Chymotrypsin / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000528:radiation effects*; D003201:Computers; D039301:Computers, Molecular; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004581:Electronics; D004789:Enzyme Activation / Q000528:radiation effects; D004791:Enzyme Inhibitors / Q000737:chemistry; D008128:Logic; D010777:Photochemistry / Q000295:instrumentation* / Q000379:methods; D011370:Proflavine / Q000737:chemistry*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D014466:Ultraviolet Rays
chemical_list: D004791:Enzyme Inhibitors; D011370:Proflavine; D002918:Chymotrypsin; C117608:alpha-chymotrypsin