A Method for the Determination of Tartrate-Labile, Prostatic Acid Phosphatase in Serum

L(+)-Tartrate strongly inhibits prostatic acid phosphatase (Abul-Fadl and King, 1948King, , 1949) ) while having no action on red cell phosphatase.The authors suggested the application of this phenomenon and its diagnostic value as a sensitive test in elucidating doubtful or borderline cases of prostatic cancer.Based on this principle, Fishman and Lerner (1953) described a method for the determination of serum acid phosphatase of prostatic origin.This method requires larger amounts of serum, besides involving the precipitation and separation of proteins, and is more complicated and time-consuming than the method in use here.The method now described is the result of further work on the tartrate-labile phosphatase component and is a modification of the aminoantipyrine (A.A.P.) methods in use in this laboratory (Kind and King, 1954).For borderline cases it probably gives a truer measure of the prostatic part of the serum acid phosphatase than does the formol-stable fraction.A somewhat similar procedure has been described by Daivis and Ward (1956).Reagents Citrate Buffer.-Crystallinecitric acid, 21 g., is dissolved in water, 188 ml. of N-NaOH added, the pH adjusted to 4.9 by cautious addition of N-NaOH or N-HCI, and made up to 500 ml.Preserve with a few drops of chloroform in the refrigerator.Substrate (0.01 M-Disodium Phenyl Phosphate).-For the substrate, dissolve 2.18 g. 0.01 M-disodium phenyl phosphate in 1 litre of freshly boiled and cooled distilled water and preserve with a few drops of chloroform in the refrigerator.Stock Phenol Standard (1 mg./ml.).-Pure crystalline phenol, 1 g., is dissolved in a litre of 0.1 N-HCl and preserved in the refrigerator.Dilute Phenol Standard (0.01 mg./ml.).-One millilitre of stock standard diluted to 100 ml. with distilled water is preserved with a few drops of chloroform in the refrigerator.0.5 N-Sodium Hydroxide.-This is stored in a polythene bottle and filtered when necessary. 0.5 m-Sodium Bicarbonate.-Sodiumbicarbonate, 4.2 g., is dissolved in water and made up to 100 ml.The solution is stored in a polythene bottle and filtered when necessary.4-Amino-antipyrine (A.A.P., 0.6 '%). -4-Amino- antipyrine, 0.6 g., is dissolved in water and made up to 100 ml.This solution should be stored in a brown bottle in the refrigerator and filtered before use.A.A.P. Reagent.-Amixture of 0.5 M-NaHCO3 and 0.6% 4-amino-antipyrine is made in the proportion of 1: 1.The mixture is stored in the refrigerator in a brown bottle and is stable for a month.Potassium Ferricyanide.-Thisreagent is made up as 2.4 g. per 100 ml. in water and kept in a brown bottle.M-Tartrate.-L(+)-Tartaric acid (AnalaR), 15 g., is dissolved in about 70 ml. of water, 18.5 ml. of 10 N-NaOH added, the pH adjusted to 4.9 and made up to 100 ml.Stored in the cold room (4' C.) or refrigerator with a few drops of chloroform, this solution is stable.A few crystals of Na-H-tartrate may form if the temperature goes below 4' C.: these will re-dissolve on slight warming.It is essential that all solutions used are optically clear.The results are shown graphically (Fig. 1).It is clear that for acid phosphatase activities in the ranges copyright.