Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 6

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  L-asparaginase
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

L-asparaginase: An ultimate anti-neoplastic enzyme

100%
Prasad Talluri V. S. S. L., Bhavana M., Mahesh Kumar M. V. S., Rajagopal S. V.
International Letters of Natural Sciences
|
2014
|
tom 10
The objective of the study described the importance of L-asparaginase and its importance in the field of medicine. Different types of enzymes are produced based on the adaptation to the environment where the living organisms live to tune the metabolic pathways according to their adapted changes. The enzymes present in various organs are produced by many cell types in multicellular organisms. Except ribosomes all other known enzymes are proteinaceous in nature. L-asparaginase is a potential therapeutic agent for acute lymphoblastic leukemia (ALL) and chronic myelogenous leukemia which is approved by FDA & WHO. L-asparaginase catalyzes the deamination of L-asparagine to L-aspartic acid & ammonia. Unlike normal cells, malignant cells require large amount of L-asparagine for protein synthesis and cell division. From this background the present review is an effort to gather the information on the mechanism, sources, molecular details and application of L-asparaginase enzyme.
2

Why a benign mutation kills enzyme activity. Structure-based analysis of the A176V mutant of Saccharomyces cerevisiae L-asparaginase I

72%
Bonthron D. T., Jaskolski M.
Acta Biochimica Polonica
|
1997
|
tom 44
|
nr 3
A conservative and apparently harmless AI76V mutation in intracellular S. cerevisiae L-asparaginase (ScerAI) completely abolishes the enzyme activity. Sequence and structural comparisons with type II bacterial L-asparaginases show that the mutated residue is in a very conservative region and plays a vital role in the cohesion of functional tetramers of these enzymes through participation in side-chain...main-chain (Ser) Oy...O (Ala) hydrogen bonds across the tetramer interface. The fact that bacterial L-asparaginases of type I show less conservation in this region suggests that they may have different quaternary structure while adopting the subunit fold and intimate dimer architecture of type II enzymes. A comparison of all available sequences of microbial L- asparaginases confirms that separate intra- and extra-cellular enzymes evolved in prokaryotes and eukaryotes independently. However, an analysis of the available complete genome sequences reveals a surprising fact that Haemophi­lus influenzae possesses only a type II asparaginase while the archaebacterium Methanococcus jannaschii has a type I gene, but not a type II.
3

Sequence analysis of enzymes with asparaginase activity

72%
Borek D., Jaskolski M.
Acta Biochimica Polonica
|
2001
|
tom 48
|
nr 4
Asparaginases catalyze the hydrolysis of asparagine to aspartic acid and ammonia. Enzymes with asparaginase activity play an important role both in the metabolism of all living organisms as well as in pharmacology. The main goal of this paper is to at­tempt a classification of all known enzymes with asparaginase activity, based on their amino acid sequences. Some possible phylogenetic consequences are also discussed using dendrograms and structural information derived from crystallographic studies.
4

Preliminary crystallographic studies of Y25F mutant of periplasmic Escherichia coli L-asparaginase

72%
Kozak M., Jaskolski M., Rohm K. H.
Acta Biochimica Polonica
|
2000
|
tom 47
|
nr 3
Periplasmic Escherichia coli L-asparaginase II with Y25F mutation in the active-site cavity has been obtained by recombinant techniques. The protein was crystallized in a new hexagonal form (P6522). Single crystals of this polymorph, suitable for X-ray diffraction, were obtained by vapor diffusion using 2-methyl-2,4-pentanediol as precipitant (pH 4.8). The crystals are characterized by a = 81.0, c = 341.1 A and diffract to 2.45 A resolution. The asymmetric unit contains two protein molecules arranged into an AB dimer. The physiologically relevant ABA'B' homotetramer is generated by the action of the crystallographic 2-fold axis along [1, -1, 0]. Kinetic studies show that the loss of the phenolic hydroxyl group at position 25 brought about by the replacement of Y with F strongly impairs kcat without significantly affecting Km.
5

Screening of Actinomycetes from mangrove ecosystem for L-asparaginase activity and optimization by response surface methodology

58%
Usha R., Mala K. K., Venil C. K., Palaniswamy M.
Polish Journal of Microbiology
|
2011
|
tom 60
|
nr 3
Marine actinomycetes were isolated from sediment samples collected from Pitchavaram mangrove ecosystem situated along the southeast coast of India. Maximum actinomycete population was noted in rhizosphere region. About 38% of the isolates produced L-asparaginase. One potential strain KUA106 produced higher level of enzyme using tryptone glucose yeast extract medium. Based on the studied phenotypic characteristics, strain KUA106 was identified as Streptomyces parvulus KUA106. The optimization method that combines the Plackett-Burman design, a factorial design and the response surface method, which were used to optimize the medium for the production of L-asparaginase by Streptomycetes parvulus. Four medium factors were screened from eleven medium factors by Plackett-Burman design experiments and subsequent optimization process to find out the optimum values of the selected parameters using central composite design was performed. Asparagine, tryptone, d))extrose and NaCl components were found to be the best medium for the L-asparaginase production. The combined optimization method described here is the effective method for screening medium factors as well as determining their optimum level for the production of L-asparaginase by Streptomycetes parvulus KUAP106.
6

Staphylococcal L-asparaginase: Catabolic repression of synthesis

58%
Rozalska M., Mikucki J.
Acta Microbiologica Polonica
|
1992
|
tom 41
|
nr 3-4
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.