ENZYME IMMUNOASSAY METHOD FOR LEUCINE ENKEPHALINE

摘要

PURPOSE:To improve measurement sensitivity and reproducibility by utilizing the fused protein genetically bonded with labeling enzyme and antigen by a gene manipulation as a labeling antibody. CONSTITUTION:The coliform bacilli contg. the plasmid having the gene coding the dihydro folic acid reductase-leucine enkephalline fused protein (hereafter expressed as DHFR-L-Enk) are prepd. by the gene manipulation and are subjected to fractionating, refining and purifying after liquid culture to obtain the DHFR-L-Enk exhibiting a uniform band in SDS electrophoresis. Said liquid is added together with an antirabbit leucine enkephalline (hereafter expressed as L-Enk) antibody to cause reaction, by which a soln. for measuring enzyme activity is obtd. A DHFR substrate soln. is then added thereto to initiate reaction. A change in the absorption at 340nm wavelength is measured by a spectrophotometer, by which L-Enk is measured.