Histochemical quantitation of gamma-glutamyl transferase in human leukemia cell lines.
The enzyme gamma-glutamyl transferase (gamma-GT) is involved in many biochemical systems, including the signal transduction of hematopoietic growth factors. Standard colorimetric gamma-GT assays require larger cell numbers than may be obtainable in many cases, such as with highly purified stem-cell populations. To study gamma-GT expression in limited populations, we used a histochemical stain to analyze gamma-GT semiquantitatively in cells of hematopoietic origin. Several human leukemic cell lines, including one with inducible increases in gamma-GT, were stained for gamma-GT and graded 0 through 4+ for the amount of positive granules. The gamma-GT activity demonstrated by this stain was found to be directly proportional to the gamma-GT activity obtained with a colorimetric assay and could be used to calculate approximate gamma-GT activity. This stain therefore provides a useful method for determining gamma-GT activity when limited cell numbers are available.
Kobb
S M
SM
Department of Medicine, College of Medicine, University of Florida.
Miller
A M
AM
D003124:Colorimetry; D016207:Cytokines / Q000494:pharmacology; D004790:Enzyme Induction; D006651:Histocytochemistry; D006801:Humans; D007938:Leukemia / Q000201:enzymology*; D013194:Staining and Labeling; D014407:Tumor Cells, Cultured / Q000201:enzymology; D005723:gamma-Glutamyltransferase / Q000096:biosynthesis / Q000378:metabolism*
D016207:Cytokines; D005723:gamma-Glutamyltransferase