Abstract
Summary
Homogenates of normal and malignant tissues were centrifuged at 18,000 g and the phosphomannose isomerase (PMI) activity of the supernatants determined. PMI activity of Jensen sarcoma and Walker carcinosarcoma 256 was equivalent to that observed in kidney or brain, but was higher than the activity of muscle. Activities in primary hepatomas, induced with 3′-methyl-4-dimethylaminoazobenzene (3′-Me-DAB) and the Novikoff hepatoma were equivalent to that of normal liver. A transplanted 3′-Me-DAB hepatoma had PMI activity 2-fold higher than normal liver, while activity in liver tissue adjacent to primary hepatomas was approximately half that observed in liver. The enzyme from the Walker tumor was inhibited by o-phenanthroline, ethylenediaminotetraacetate and p-chloromercuribenzoate (CMB). CMB inhibition was partially reversed by cysteine.
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