Two L-asparaginases from E. coli and their action against tumors.
Year: 1966
Type: article
Abstract: Normal guinea pig serum inhibits the growth of a number of transplantable mouse and rat tumors in vivo, and evidence has been presented that this is brought about by its content of L-asparaginase.IRecently it has been shown that aspar- aginases from E. coli2 and S. marcescens3 also possess antitumor activity, but enzymes from other microbial sources have been ineffective.2' 4We have found that, depending upon the conditions of growth, E. coli cells possess one or two asparaginase activities.This is due to two distinct enzymes which differ in a number of properties, most significantly in their affinities for L-asparagine.The enzyme with the higher affinity markedly inhibited lymphomas in mice, while the aspar- aginase with the lower affinity was ineffective.Agouti serum, which contains an L-asparaginase with an affinity intermediate between those of the two enzymes from E. coli, inhibited tumors less than did the E. coli enzyme with the higher affinity.We conclude that the affinity of asparaginase for its substrate is related to its degree of effectiveness against sensitive tumors.
Authors: J H Schwartz, J Y Reeves, J D Broome
Language: English
Subfield: Biochemistry
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2086930991