title: Human prostatic acid phosphatase: purification, characterization, and optimization of conditions for radioimmunoassay.
abstract: Prostatic acid phosphatase was isolated from benign hypertrophic prostate tissue by ammonium sulfate precipitation and affinity chromatography procedures. The purified enzyme was characterized by two-dimensional gel electrophoresis and shown to have a cluster of protein spots with an apparent molecular weight of 48 000 at pI 5.9 to 6.3 in 9 mol/l urea. The specific activity of the purified enzyme was 723 and 659 U/mg protein with alpha-naphthyl phosphate at 30 degrees C and para-nitrophenyl phosphate at 37 degrees C respectively. An antibody to the purified enzyme was raised in rabbits and used in a radioimmunoassay (RIA). The use of a phosphate buffer, pH 6.6, and iodination of prostatic acid phosphatase (PAP) by the Bolton-Hunter procedure improved the precision of the assay when compared to RIA's using a phosphate buffer, pH 7.0 or 7.3, or PAP iodinated by a chloramine-T procedure. The former RIA displaced 50% of the tracer at 2 micrograms of enzyme per liter of serum. The between-run coefficient of variation for 11 assays ranged from 3.9-7.7% with serum at 1.3 to 5.6 micrograms PAP/l.
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis* / Q000302:isolation & purification; D006801:Humans; D007526:Isoelectric Point; D008297:Male; D008970:Molecular Weight; D011467:Prostate / Q000201:enzymology*; D011470:Prostatic Hyperplasia / Q000201:enzymology; D011863:Radioimmunoassay / Q000379:methods
chemical_list: D000135:Acid Phosphatase