Mouse Anti-Human p504s monoclonal antibody, clone JID615

alpha-Methylacyl-CoA racemase (AMACR) is an important enzyme for the metabolism of branched-chain lipids and drugs. The enzyme is over-expressed in prostate and other cancers. AMACR 1A, the major splice variant, was purified from recombinant E. coli cells as a His-tag protein. Purified enzyme catalysed chiral inversion of both S- and R-2-methyldecanoyl-CoA, with an equilibrium constant of 1.09 +/- 0.14 (2S/2R). Reactions with H-2-labelled substrate showed that loss of the alpha-proton was a prerequisite for chiral inversion. Reactions conducted in (H2O)-H-2 indicated that reprotonation was not stereospecific. These results are the first mechanistic study on any recombinant mammalian alpha-methylacyl-CoA racemase.

Background: Differentiation between normal renal cellular structures and renal tumors can be a diagnostic challenge during fine needle aspiration. It is of particular relevance during percutaneous thermal ablation because of the small size of tumors and when performing rapid on-site evaluation. Methods: A cyto-histological correlation study assisted by immunocytochemistry was performed. The study was based on 10 nephrectomy specimens. For the identification of proximal tubular cells we used CD10 and alpha-methylacyl coenzyme A racemase (AMACR). PAX8 and GATA3 were used for the recognition of distal and collecting duct cells. For a precise correlation representative cytologic groups were photographed before and after immunocytochemistry. Results: All cases showed: (a) glomeruli; (b) presence of at least 2 different epithelial cell populations that distribute separately, one representing the proximal tubule and the other more distal segments; and (c) existence of isolated, laminar basement fragments and slender, intact tubular structures. Proximal tubular cells were large with granular cytoplasm, indistinct cell borders, moderate anisonucleosis, and variable presence of pigment. Their immunophenotype was CD10+, AMACR+, PAX8-, and GATA3-. In all cases, cellular aggregates different of nonproximal tubular cells were present. They were smaller than proximal tubular cells with less cytoplasm, better-defined cell borders and uniform nuclei. Their immunophenotype was CD10-, AMACR-, PAX8+, and GATA3+ Conclusion: Aspirates from the normal kidney show characteristic features that permit a specific recognition. Different segments of the tubular system can be specifically recognized avoiding confusion with renal tumors. In difficult cases immunocytochemistry is a very helpful aid.