title: 8-quinolyl phosphate as a substrate for the fluorimetric determination of alkaline phosphatase.
abstract: BACKGROUND
  Alkaline phosphatase (ALP) is an important target for clinical analysis. 8-Quinolyl phosphate (QP) was developed as a new substrate for the fluorimetric determination of ALP activity.
  
  
  METHODS
  QP is a strong fluorescent substance and the product of the enzyme reaction is 8-hydroxyquinoline (HQ), which has no fluorescence. Under the optimal conditions for the determination of ALP, the decreased fluorescence intensity via the enzyme reaction is proportional to ALP activity. The fluorescence intensity was measured at lambdaex/lambdaem=318/495 nm before and after the enzyme reaction.
  
  
  RESULTS
  QP reacted with ALP in the buffer solution of pH=9.5 and incubated for 20 min at 37.0 degrees C were selected as the optimal conditions for the determination of ALP. The linear range and detection limit for the determination of ALP are 1.0-16.0 and 0.229 U/l, respectively. With this method, ALP could be applied to assess ALP in human serum and the results were evaluated by comparison with a standard colorimetric assay using p-nitrophenyl phosphate as ALP substrate.
  
  
  CONCLUSIONS
  This method is simple, practical and can be used as an alternative to assess ALP in clinical analysis.
authors.affiliation: Department of Chemistry, Shandong Normal University, Jinan, 250014, China.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Zhu
authors.forename: Chongqiu
authors.initials: C
authors.lastname: Jiang
mesh_terms: D000469:Alkaline Phosphatase / Q000032:analysis* / Q000378:metabolism*; D005470:Fluorometry; D020662:Guanine Nucleotide Exchange Factors; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D010755:Organophosphates / Q000737:chemistry / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D011804:Quinolines / Q000737:chemistry / Q000378:metabolism*; D064067:Rho Guanine Nucleotide Exchange Factors; D013379:Substrate Specificity; D013696:Temperature
chemical_list: C517653:8-quinolyl phosphate; C577228:ARHGEF5 protein, human; D020662:Guanine Nucleotide Exchange Factors; D010755:Organophosphates; D011518:Proto-Oncogene Proteins; D011804:Quinolines; D064067:Rho Guanine Nucleotide Exchange Factors; D000469:Alkaline Phosphatase