Characterization of sialytransferase in noncancerous and neoplastic human liver tissue
Ingraham, H.A.; Alhadeff, J.A.
Journal of the National Cancer Institute 61(6): 1371-1374
1978
ISSN/ISBN: 0027-8874 PMID: 82633 Document Number: 133686
When compared to uninvolved adjacent tissue, metastatic tumors in human liver appear to have significantly reduced sialyltransferase activity. No significant kinetic differences (Michaelis constants, thermostability and pH optima) between noncancerous and cancerous tissue sialyltransferase were found. Mixing experiments between cancerous and noncancerous tissues indicated that inhibitors of sialyltransferase activity were present in cancerous tissue. Subsequent experiments demonstrated increased levels of bound sialic acid in the tumor tissues. Inasmuch as fetuin, a sialoglycoprotein, inhibits sialyltransferase activity, the increased levels of bound sialic acid in tumor tissue may be responsible for the reduced enzyme activity in these tissues.