Purification and characterization of a fatty acid binding protein from human prostatic tissue

Abstract

Epidemiological studies suggest the existence of a strong relationship between the incidence of prostatic cancer and the intake of dietary lipids in humans. However, very little information is available on intracellular fatty acid metabolism in human prostatic tissue. The objective of this study was to identify and subsequently characterize a fatty acid binding protein of human prostatic tissue. A fatty acid binding protein (FABP) was purified and characterized from human prostatic tissue. The purified FABP had an apparent molecular mass of 15.0 +/- 1.0 kDa as averaged from three different methods, sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE), gel filtration and amino acid analysis. The pI value of the protein was determined to be 6.8. Scatchard analysis of fatty acid binding to the purified FABP from malignant prostatic tissue showed a Kd value of 0.53 +/- 0.02 microM for arachidonic acid (n = 5). The Kd values of FABP purified from benign prostatic tissue were 0.57 +/- 0.02 microM for oleic acid and 0.51 +/- 0.04 microM for arachidonic acid (n = 5). Fatty acid analysis revealed that the level of endogenously bound arachidonic acid was about 2.5-fold higher in FABP from malignant than from benign tissue. In addition, both malignant and benign tissues contained the same concentration of FABP. The concentrations of FABP in malignant and benign tissues were 19.2 +/- 1.8 and 21.4 +/- 2.1 micrograms per mg of total cytosolic protein, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)