Comparison of Prostatic and Nonprostatic Acid Phosphatase*

Abstract

Electrophoresis and ion-exchange column chromatography were used to separate the wide varieties of acid phosphatases with different biological and clinical significance. Band 0 was very strong in ascitic cells with many autophagic vacuoles, indicating a role in autophagic function. Band 1 was a membrane-bound acid phosphatase, seen mainly in the microsomal fraction. Band 3 was the major lysosomal acid phosphatase of all nonprostatic tissues. Bands 2 and 4 were antigenically identical to each other, and were observed in unusually high amounts in the prostate. The different electrophoretic mobility between bands 2 and 4 was due to their carbohydrate content. Band 5 was a characteristic enzyme of the osteoclast. The tartrate-sensitive enzymes included bands 0 through 4. Only band 5 was tartrate resistant. The tartrate-resistant acid phosphatase of erythrocytes was not detected by the electrophoresis method. Clinical applications were seen for both bands 2 and 5. Band 2 was a secretory enzyme, normally secreted into the seminal plasma. Band 2 was absorbed into the blood circulation in some prostatic cancer patients. A small amount of bands 2 and 4 was observed in nonprostatic tissues. The diagnostic value of band 2 resulted from its extremely high concentration in the prostate. Band 5 was not observed in the normal prostate. A high concentration of band 5 was observed in hairy cells, Gaucher cells, and osteoclasts. The serum level of band 5b was an indicator of osteoclastic activity in the bone. Elevation of band 5b in serum was observed in normal children during physiological bone growth, in Gaucher's disease, and in malignancies metastasized to bone.

Tartrate-Resistant Acid Phosphatase of Human Lung: Apparent Identity with Osteoclastic Acid Phosphatase

“…The gene which determines osGiant cell tumour [12] Leukaemic reticulo endotheliosis spleen [11] Gaucher's disease spleen [5] (30,000 [13] …”

Tyrosyl kinase activity is inversely related to prostatic acid phosphatase activity in two human prostate carcinoma cell lines.

“…One of these phosphatases is the major isoenzyme of prostatic acid phosphatase (PAcP) (13,14), which is synthesized primarily in prostate tissue and is the most abundant phosphatase in that tissue (12,28). The major species of PAcP preferentially dephosphorylates phosphotyrosine residues in proteins (13,14) and has a very high affinity (Ki,m 10-9 M) for phosphotyrosine-containing proteins (14).…”

“…LNCaP cells had about twice as much total cellular acid phosphatase activity as did the DU145 cells (Table 1). Tartrate sensitivity was used to distinguish between PAcP and other phosphatases, since tartrate is a specific inhibitor of PAcP which does not affect alkaline or most other acid phosphatase activities (12,28). The differences in acid phosphatase activities in these cells were mainly from acid phosphatase activity inhibited by 10 mM tartrate (Table 1).…”

Comparison of prostate acid phosphatase with acid phosphatase isoenzymes from the lung and spleen

“…The enzymatic similarity is indicated by their substrate and inhibitor specificity. For example, L( + )-tartrate, a potent and specific inhibitor commonly used for PAP and lysosomal acid phosphatase (1,23,24), also inhibits SAP and LAP equally and effectively well. p-Nitrophenyl phosphate, a classic substrate of PAP, is also dephosphorylated by LAP and SAP.…”