N4-Ethyl-L-[u-14C]asparagine and L-[U-14C]aspartate give identical metabolites, mainly intermediates of the tricarboxylic acid cycle and related amino acids, in whole cells of Pseudomonas stutzeri. The labelled asparagine derivative is converted into [14C]-aspartate by cell-free extracts, and this reaction, which has an optimum pH of 8.8 +/- 0.2, is neither inhibited by unlabelled asparagine no...

Perovskite Solar Cells In article number 2302418, Hyungjun Kim, Ki-Ha Hong, Sang Hyuk Im, Chang Eun Song, and co-workers demonstrate a defect-passivation strategy using L-asparagine, which can effectively suppress tin oxidation. L-asparagine as zwitterion revolutionizes film morphology energy-level matching, boosting power conversion efficiency to remarkable 13.31%. Surpassing limitations are t...

THE occurrence of asparagine in the higher plant and its role in protein metabolism have formed the subject of numerous investigations. It has been found that the amount normally present in the green plant is very small and it is only under artificial conditions, associated with a carbohydrate deficiency, that an accumulation of this substance is ever obtained. E. Schulze [1906], in a series of...

L-Asparagine is responsible for a major portion of the effect of peptone on the growth of L5178Y lymphoblasts in culture and is essential for the reproduction of these cells. Among the compounds tested, the requirement for the amide is replaced only by certain peptide derivatives of asparagine, and these are less active on a molar basis than is L-asparagine; L-aspartic acid, D-asparagine, and L...

care is taken to inhibit ex vivo enzyme activity.4 We sent a blinded set of our samples to Dr Asselin, and she confirmed the asparagine values we reported. Liver perfusion studies and modeling of asparaginase treatment suggest that there is a high rate of asparagine input into the circulation from diet and the tissues.5,6 An equilibrium between the rate of asparagine input and the asparaginase ...

The conserved Asn 229 of thymidylate synthase (TS) forms a cyclic hydrogen bond network with the 3-NH and 4-O of the nucleotide substrate 2'-deoxyuridine 5'-monophosphate (dUMP). Asn 229 is not essential for substrate binding or catalysis [Liu, l., & Santi, D. B. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 8604-8608] but is a major determinant in substrate specificity [Liu, l., & Santi, D. V. (199...

care is taken to inhibit ex vivo enzyme activity.4 We sent a blinded set of our samples to Dr Asselin, and she confirmed the asparagine values we reported. Liver perfusion studies and modeling of asparaginase treatment suggest that there is a high rate of asparagine input into the circulation from diet and the tissues.5,6 An equilibrium between the rate of asparagine input and the asparaginase ...

The activity of asparagine synthetase in Chinese hamster ovary (CHO) cells is increased in response to asparagine deprivation or decreased aminoacylation of several tRNAs (Andrulis, I. L., Hatfield, G. W., and Arfin, S. M. (1979) J. Biol. Chem. 254, 10629-10633). CHO cells resistant to beta-aspartylhydroxamate have up to 5-fold higher levels of asparagine synthetase than the parental line (Gant...

Asparagine is present in the mature leaves of young pea (Pisum sativum cv Little Marvel) seedlings, and is synthesized in detached shoots. This accumulation and synthesis is greatly enhanced by darkening. In detached control shoots, [(14)C]aspartate was metabolized predominantly to organic acids and, as other workers have shown, there was little labeling of asparagine (after 5 hours, 3.1% of me...

SUMMARY Resistance to L-asparagine depletion in tumor cells has been correlated with asparagine biosynthesis mediated by the enzyme asparagine synthetase. In this study , we describe certain characteristics of the asparagine synthetase of the KB human tumor cell carried in tissue culture. The KB enzyme is similar to that of other mammalian tumors in terms of c ofactor requirements and inhibitio...