Abstract
OBSERVATIONS in this laboratory on various homogenates and on tumour ascites fluid1,2 have suggested that a component in blood plasma acts as a powerful cathepsin inhibitor. In order to study this interesting finding, cathepsins B and D were first separated by gel filtration from the lysosomal pellet of calf liver homogenates and subsequently studied in their partially purified form. For the colorimetric assays edestin denatured with urea was used as a substrate in 0.1 molar acetate buffer at pH 5.0 according to Ottoson and Sylvén1. Both 0.004 molar cysteine and 0.05 EDTA must be added for maximum cathepsin B activity. Without their addition, or with added cysteine alone, extinction increments which were too small and erratic were obtained. By means of this system the cathepsin B and D activity changes could then be studied separately after the addition of small amounts of all the different available purified plasma protein fractions from normal human blood. One fraction only prepared from Cohn's fraction IV–b containing the haptoglobins exhibited a marked inhibitory effect on the cathepsin B activity. This inhibition was noted even at weak haptoglobin concentrations amounting to a quarter of the amount of enzyme. No inhibition was found on addition of other highly purified serum proteins such as transferrin, ceruloplasmin or α1-acid glycoprotein, nor by addition of pure sialic acid, which is a component of haptoglobin. The cathepsin D activity, however, remained totally uninfluenced by all of the plasma fractions.
Similar content being viewed by others
Article PDF
References
Ottoson, R., and Sylvén, B., Arch. Biochem. Biophys., 87, 41 (1960).
Sylvén, B., Ottoson, R., and Révész, L., Brit. J. Cancer, 13, 551 (1959).
Lineweaver, H. A., and Burk, D., J. Amer. Chem. Soc., 56, 658 (1934).
Goldbarg, J. A., and Rutenburg, A. M., Cancer, 11, 283 (1958).
Dobryszycka, W., and Lisowska, E., Biochim. Biophys. Acta, 121, 42 (1966).
Laurell, C.-B., and Grönvall, C., in Adv. Clin. Chem. (edit. by Sobotka, H., and Stewart, C. P.), 5, 135 (Academic Press, New York, 1962).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
SNELLMAN, O., SYLVÉN, B. Haptoglobin acting as a Natural Inhibitor of Cathepsin B Activity. Nature 216, 1033 (1967). https://doi.org/10.1038/2161033a0
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1038/2161033a0
This article is cited by
-
Purification of haptoglobin and its effects on lymphocyte and alveolar macrophage responses
Inflammation (1983)
-
The inhibition of cathepsin B by plasma haptoglobin biochemistry (enzymes, metabolism)
Experientia (1981)
-
Type-dependent difference in the metabolism of human haptoglobins
Japanese journal of human genetics (1979)
-
Immunofluorescent studies on the occurrence of cathepsin B1 at tumor cell surfaces
Virchows Archiv B Cell Pathology (1975)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.