Asparaginase other

The major indication for L-asparaginase is in the treatment of acute lymphoblastic leukemia complete remission rates of 50 to 60% are possible. Lack of crossresistance and bone marrow toxicity make the enzyme particularly useful in combination chemotherapy, l-Asparaginase also can be used in the treatment of certain types of lymphoma. It has no role in the treatment of nonlymphocytic leukemias or other types of cancer. 

B. Indications and use Oncaspar is indicated for patients with ALL who require L-asparaginase in their treatment regimen but have developed hypersensitivity to the native forms of the enzyme. Oncaspar, like native L-asparaginase, is generally used in combination with other chemotherapeutic agents, such as vincristine, methotrexate, cytarabine, daunorubicin, and doxorubicin. 

Penicillin and related antibiotics are inactivated by P-lactamases (Box 20-G), some of which resemble serine proteases in forming acyl enzymes with active site serine side chains.656 657 Others are zinc metallogen-zymes.658/659 Amidohydrolases such as asparaginase and glutaminase,660/661 deacetylases,662 and many other hydrolases can also be described as acyltransferases. 

The presence of asparaginase in guinea pig serum was first reported by Clementi (10), who also noted the absence of this enzyme in the sera of a number of other common mammals including the rat, cat, dog, monkey, and human. The list of animal sera from which asparaginase... 

M. phlei, and several strains of M. tuberculosis (28-30) contain a true asparaginase, as do extracts of Bacillus coagulans and Bacillus stearo-thermophilus (31). Brucella abortus contains two asparaginases, one specific for L-asparagine and the other for the opposite enantiomorph (32). An asparaginase is also present in Pseudomonas fluorescens (33). Also, Tsuji, in 1957, had reported the presence of asparaginase in extracts of acetone powders of E. coli, Staphylococcus, M. avium, and Aspergillus oryzae (34). 

Lee and Bridges (13) have confirmed the absence of asparaginase in the serum of a variety of animal species and in 25 human sera but have observed that human and sheep sera, themselves devoid of detectable asparaginase activity, enhanced the activity of guinea pig serum (GPS). Other sera did not show this effect with the GPS enzyme, but all the sera enhanced E. coli asparaginase activity. Further work by these authors (47) and by Ho and Jones (48) indicates that the effect results from a nonspecific stabilization by plasma proteins. 

It is difficult to draw an accurate comparison with GPS asparaginase, the only other asparaginase whose amino acid composition has been... 

Protein synthesis is the only known major role for asparagine in mammalian systems. Both Sobin and Kidd (99) and Broome (91) have shown that the capacity of asparagine-dependent tumors to synthesize protein is impaired in the absence of this amino acid. Nevertheless, the question is not yet resolved as to whether the dramatic effect of asparaginase on leukemic cells can be ascribed solely to interference with this process or whether other metabolic functions are affected indirectly. Ryan and Sornson (100) have shown recently that the administration of asparaginase depressed the level of tumor glycine specifically in... 

Others Asparaginase Degradation of L-asparagine Erwinia chrysanthemi Treatment of acute... 

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