Chromogenic substrates for cholinesterases: 1-[2-Thiazolylazo]-2-acetoxybenzene derivatives

✍ Scribed by C. van Hooidonk; C. de Borst; F.A. Mitzka; C.C. Groos

• Publisher: Elsevier Science
• Year: 1972
• Tongue: English
• Weight: 624 KB
• Volume: 48
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(72)90167-4

✦ Synopsis

For the determination of cholinesterases it is convenient to have a direct spectrophotometric observation of the substrate hydrolysis. Acetylsalicylic acid (1) , benzoylcholine (21, a-naphthyl acetate (3)) indophenyl acetate (4)) 2,&dichloroindophenyl acetate ( 5)) and l-methylacetoxyquinolinium iodides ( 6) have been used as substrates in such procedures.

We report here on a new t.ype of chromogenic substrate (I) derived from well-known heterocyclic azo dyestuffs t'hat have found a wide application in analytical chemistry for the spcctrophotometric determination of metal ions (7,8). A difference in color exists between the ester (I) and the alcohol (II) at the pH at, which the alcohol dissociates. This difference in color can be used for the spectrophotometric assay of cholinesterases. Ye CH Ye CH /3 /3 CH o=c /3 CHOLINESTERASE +CH3CO0 e pH 7.0 5 I II S = .5-CH3, Y = CHoSOl (IA), light yellowbl ue (IIAI S = 4-N(CH,)L, Y = I (IB), blue -red (IIH) M.ATKR1AI.S .AXI:, METHODS 2-Aminothiazole (m.1~. S8.590°C') was obtainccl from EGA-Chemic~ KG (Germany).