Differences in the enzymatic nature and the sugar-chain structure of gamma-glutamyl transferase between normal and carcinomatous human kidney and prostate.
The enzymatic and immunological nature, and the sugar chain structure, of gamma-glutamyl transferase (GGT) purified from tissues of benign prostatic hypertrophy (BPH), prostatic carcinoma (PCa) and renal cell carcinoma (RCa), were compared with those of the normal prostate (NP) and kidney (NK). The specific activities of GGTs in NP, NK, BPH, PCa and RCa were 78.9, 22.5, 105, 92.5 and 52.5 mU/mg protein, respectively. The molecular masses of GGTs from BPH, PCa and RCa were 72 kDa, 78 and 108 kDa, and 79 and 105 kDa, respectively. The Michaelis constants (Km), optimum pHs and the inhibition of GGT activities by several chemical compounds, revealed that the GGT from BPH, PCa and RCa was similar to that of normal GGT. Immunologically, the IgG fraction against anti-human seminal plasma GGT fused to the all of the GGTs tested. The sugar chain heterogeneities of the various GGTs, detected by the serial-lectin affinity technique, differed from one another. The sugar chain of GGT from BPH resembled the sugar chain from NP. On the contrary, the sugar chains of GGTs from PCa and RCa were markedly different from those from normal tissues. In the GGT from PCa, multi-antennary complex type sugar chains were more increased than the enzyme of NP. In general, as previously reported, the sugar chains of GGTs from carcinomatous tissues of prostate and kidney had an increased content of bisecting GlcNAc (beta 1-->4) containing complex type sugar chains. Moreover, the reductions of the biantennary complex type sugar chain with fucose linkage and the hybrid type sugar chain were obvious in the GGT from carcinomatous tissues of the prostate and kidney.