title: Assay of serum/plasma beta-N-acetylhexosaminidase isoenzymes by heat inactivation using a continuous spectrophotometric method adapted to a centrifugal analyzer.
abstract: Activity of serum/plasma beta-N-acetylhexosaminidase (EC 3.2.1.52) was determined by means of a continuous spectrophotometric method using 3,3'-dichlorophenylsulphonphthaleinyl-N-acetyl-beta-D-glucosaminid e as substrate, with very satisfactory results. Incubation of an undiluted aliquot (1 ml) of samples at 52 degrees C for 8 hours with an adjusted pH 5.5-6.0 provoked only the inactivation of isoenzyme A, thus allowing the evaluation of beta-N-acetylhexosaminidase isoenzyme composition. In 25 serum samples from control subjects and pregnant women, a good correlation between the percentage of isoenzyme B obtained by this procedure and the fluorimetric assay of O'Brien et al. (New Engl J Med 1970; 273:15-20) was found (r = 0.983, S(yx) = 1.51), with no statistically significant difference between the means (43.2 vs 42.8%). In 84 healthy adult subjects, an average value of 30.3% for the proportion of isoenzyme B was obtained, with an interval of 25.4-35.0%, in agreement with results reported by other authors.
authors.affiliation: Laboratorio Central, Hospital General de Galicia-Clínico Universitario, Santiago de Compostela, Spain.
authors.forename: L F
authors.initials: LF
authors.lastname: Pérez
authors.forename: J C
authors.initials: JC
authors.lastname: Tutor
mesh_terms: D000328:Adult; D001774:Blood Chemical Analysis / Q000379:methods* / Q000706:statistics & numerical data; D005069:Evaluation Studies as Topic; D005260:Female; D005470:Fluorometry / Q000379:methods; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000032:analysis / Q000037:antagonists & inhibitors / Q000097:blood*; D008297:Male; D011247:Pregnancy; D012016:Reference Values; D013053:Spectrophotometry / Q000379:methods* / Q000706:statistics & numerical data; D001619:beta-N-Acetylhexosaminidases / Q000032:analysis / Q000037:antagonists & inhibitors / Q000097:blood*
chemical_list: D007527:Isoenzymes; D001619:beta-N-Acetylhexosaminidases