Crithidia fasciculata tyrosine transminase

Constantsas, N.S.; Levis, Gabriel M.; Vakirtzi-Lemonias, Catherine

doi:10.1016/0304-4165(71)90061-4

Cited by 12 publications

(3 citation statements)

References 22 publications

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“…Since that time, this transamination phenomenon has been subject to extensive study and speculation. Constantsas et al (2) (4). In vivo experiments in acutely infected mice or chronically infected Microtus montanus clearly showed that African trypanosomes produce transamination metabolites in sufficient quantities to lead to aromatic acidemia and elevated urinary excretion of aromatic keto acids (5).…”

mentioning

confidence: 99%

Aromatic amino acid transamination and methionine recycling in trypanosomatids.

Berger¹,

Dai²,

Wang³

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

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Although trypanosomatids are known to rapidly transaminate exogenous aromatic amino acids in vitro and in vivo, the physiological significance of this reaction is not understood. In postmitochondrial supernatants prepared from Trypanosoma brucei brucei and Crithidia fasciculata, we have found that aromatic amino acids were the preferred amino donors for the transamination of a-ketomethiobutyrate to methionine. Intact (8,9). To date, the aromatic amino acid transaminase has been purified from C. fasciculata (10) and T. cruzi (9), but little has been done beyond confirming that the purified enzymes transaminate tyrosine, phenylalanine, and tryptophan when using a-ketoglutarate, pyruvate, or oxaloacetate. The purified enzymes also were found to have a broad resemblance to mammalian tyrosine transaminase.Despite the extensive research into this transamination process, the physiological reason for the reactions remains unknown. Seed et al. (5)

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mentioning

confidence: 99%

Aromatic amino acid transamination and methionine recycling in trypanosomatids.

Berger¹,

Dai²,

Wang³

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

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“…The presence of TAT has as described previously [13]. The cells were washed twice in a been reported in Crithidia fasciculata [6] and in the ciliate solution containing 25 mM potassium-phosphate buffer, pH 7.8,…”

Section: Introductionmentioning

confidence: 99%

Purification and partial structural and kinetic characterization of tyrosine aminotransferase from epimastigotes of Trypanosoma cruzi

Montemartini

Santomé

Cazzulo

et al. 1993

Biochemical Journal

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Tyrosine aminotransferase was purified to homogeneity from epimastigotes of Trypanosoma cruzi by a method involving chromatography on DEAE-cellulose, gel filtration on Sephacryl S-200 and chromatography on Mono Q in an f.p.l.c. system. The purified enzyme showed a single band in SDS/PAGE, with an apparent molecular mass of 45 kDa. Since the apparent molecular mass of the native enzyme, determined by gel filtration, is 91 kDa, the native enzyme is a dimer of similar subunits. The amino-acid composition was determined, as well as the sequences of three internal peptides obtained by CNBr cleavage at Met residues. Both criteria suggest considerable similarity with the tyrosine aminotransferases from rat and from human liver. The enzyme contains nine 1/2 Cys residues, three free and the others forming three disulphide bridges. The enzyme is not N-glycosylated. The isoelectric point is 4.6-4.8. The optimal pH for the reaction of the enzyme with tyrosine as a substrate is 7.0. The apparent Km values for tyrosine, phenylalanine and tryptophan, with pyruvate as a co-substrate, were 6.8, 17.9 and 21.4 mM, respectively, whereas those for pyruvate, alpha-oxoglutarate and oxaloacetate, with tyrosine as a substrate, were 0.5, 38 and 16 mM respectively. The purified tyrosine aminotransferase acts as an alanine aminotransferase as well and the activity seems to reside in the same enzyme molecule. The results suggest that the enzyme is a general aromatic-amino-acid transaminase, with high sequence similarity to tyrosine aminotransferases from rat and human liver.

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“…* Π.χ. ή δραστικότης τής τρανσαμινάσης τής τυροσίνης αυξάνεται παροδικώς μόνον κατά τήν εναρξιν καθώς καί μετά το τέλος τής λογαριθμικής φάσεως αναπτύξεως των Κριθιδίων 135 . Επίσης, ενώ κατά τήν αρχήν τής αναπτύξεως των τα Κριθίδια οξειδώνουν τα λιπαρά οξέα δι' αμφοτέρων των α-καί β-μεταβολικών οδών, εις τα γηραιότερα κύτταρα ή όξείδωσις επιτε λείται κυρίως δια τής όδοΰ τής α-οξειδώσεως 136 .…”

Section: συμπερασματαunclassified

Συμβολη Εις Την Μελετην Της Βιοσυνθεσεως Και Της Φυσιολογικης Σημασιας Των Ουδετερων Αλκυλογλυκερολων

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Γλυκερυλομονοαιθέρες 11 Χημική σύνταξις 11 Φυσικαί πηγαί 13 Γλυκερυλοδιαιθέρες Χημική σύνταξις και φυσικαί πηγαί Μεταβολισμός των ουδετέρων άλκυλογλυκερολών Καταβολισμός Βιοσύνθεσις Φυσιολογική σημασία των ουδετέρων άλκυλογλυκερολών ΜΕΘΥΛΟΓΛΥΟΞΑΛΗ ΕΙΔΙΚΟΝ ΜΕΡΟΣ ΥΛΙΚΟΝ ΚΑΙ ΜΕΘΟΛΟΙ Άπομόνωσις μυελοϋ οστών Έπώασις ακεραίων κυττάρων Έκχύλισις λιπιδίων Χρωματογραφία επί στήλης Florisil Χρωματογραφία επί στήλης πυριτικού οξέος Χρωματογραφία επί λεπτής στιβάδος Ήπία αλκαλική ύδρόλυσις Μέτρησις ραδιενέργειας Καλλιέργεια Κριθιδίων

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Crithidia fasciculata tyrosine transminase

Cited by 12 publications

References 22 publications

Aromatic amino acid transamination and methionine recycling in trypanosomatids.

Aromatic amino acid transamination and methionine recycling in trypanosomatids.

Purification and partial structural and kinetic characterization of tyrosine aminotransferase from epimastigotes of Trypanosoma cruzi

Συμβολη Εις Την Μελετην Της Βιοσυνθεσεως Και Της Φυσιολογικης Σημασιας Των Ουδετερων Αλκυλογλυκερολων

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