Acid phosphatase enzyme measurements are regularly performed in connection with the diagnosis and treatment of human prostatic cancer. Besides carcinoma of the prostate, changes in acid phosphatase levels occur in other types of malignant growth, in hairy cell leukemia, in the congenital disorder known as Gaucher's disease, and in a fatal genetic disease characterized by a lack of acid phosphatase. Despite this, little is known about the structural and catalytic properties, and biological role, of the diverse group of enzymes known as acid phosphatases. The present project continues an investigation of the fundamental enzymology of acid phosphatases. The comparative biochemistry and mechanism of action of acid phosphatase enzymes from human prostate, human seminal fluid, bovine liver, human liver and sunflower seed are being examined. Active site peptides are being isolated and partial sequence data are being obtained for them. The structural basis of isoenzyme variation is being determined. Human prostatic and seminal fluid acid phosphatases lacking the usual N-linked carbohydrate residues are being prepared by biosynthesis or by removal of the chains from the homogeneous enzymes using homogeneous peptide N-glycosidases. Extensive sequence data are being obtained for the human prostatic and seminal fluid acid phosphatases. The stereochemistry of hydrolysis and of transfer reactions of phospho substrates are being studied. In addition, the use of the 18O isotope shift in 13C nuclear magnetic resonance spectroscopy is being used to obtain information about oxygen exchange reactions and the mechanisms of enzymatic reactions, including those catalyzed by phosphatases, peptidases and other hydrolases such as asparaginase. The substrate specificity of homogeneous peptide:N-glycosidases will be studied using a series of glycopeptides in which the amino acid and the carbohydrate components are systematically varied. The mechanism of action of the homogeneous peptide N-glycosidases will be studied using NMR to identify potential intermediates and products.
Showing the most recent 10 out of 61 publications
