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001-es BibID:	BIBFORM018946
Első szerző:	Mótyán János András (biokémikus, molekuláris biológus)
Cím:	Transglycosylation by barley alfa-amylase 1 / Mótyán János A., Fazekas Erika, Mori Haruhide, Svensson Birte, Bagossi Péter, Kandra Lili, Gyémánt Gyöngyi
Dátum:	2011
ISSN:	1381-1177
Megjegyzések:	The transglycosylation activity of barley alfa-amylase 1 (AMY1) and active site AMY1 subsite mutant enzymes was investigated. We report here the transferase ability of the V47A, V47F, V47D and S48Y single mutants and V47K/S48G and V47G/S48D double mutant AMY1 enzymes in which the replaced amino acids play important role in substrate binding at subsites at-3 through-5. Although mutation increases the transglycosylation activity of enzymes, in the presence of acceptors the difference between wild type and mutants is not so significant. Oligomer transfer reactions of AMY1 wild type and its mutants were studied using maltoheptaose and maltopentaose donors and different chromophore containing acceptors. The conditions for the chemoenzymatic synthesis of 4-methylumbelliferyl-alfa-d-maltooligosaccharides (MU-alfa-d-MOSs) were optimized using 4-methylumbelliferyl-alfa-d-glucoside as acceptor and maltoheptaose as donor. 4-Methylumbelliferyl-alfa-d-maltoside, -maltotrioside, -maltotetraoside and -maltopentaoside have been synthesized. Products were identified by MALDI-TOF MS. 1H and 13C NMR analyses showed that AMY1 V47F preserved the stereo- and regioselectivity. The produced MU-alfa-d-MOSs of degree of polymerization DP 2, DP 3 and DP 5 were successfully applied to detect activity of Bacillus stearothermophilus maltogenic alfa-amylase, human saliv
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban Barley alpha-amylase 1 Transglycosylation Methylumbelliferyl-glycosides Chemoenzymatic synthesis Amylase assay
Megjelenés:	Journal Of Molecular Catalysis B-Enzymatic. - 72 : 3-4 (2011), p. 229-237. -
További szerzők:	Fazekas Erika (1985-) (kémikus) Mori, Haruhide Svensson, Birte Bagossi Péter (1966-2011) (biokémikus, vegyész) Kandra Lili (1943-) (biokémikus) Gyémánt Gyöngyi (1960-) (vegyész)
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001-es BibID:	BIBFORM013253
Első szerző:	Mótyán János András (biokémikus, molekuláris biológus)
Cím:	Computer-aided subsite mapping of alpha-amylases / János A. Mótyán, Gyöngyi Gyémánt, János Harangi, Péter Bagossi
Dátum:	2011
Megjegyzések:	Subsite mapping is a crucial procedure in the characterization of alpha-amylases (EC 3.2.1.1), which are extensively used in starch-based industries and in diagnosis of pancreatic and salivary glands disorders. A computer-aided method has been developed for subsite mapping of alpha-amylases, which substitutes the difficult, expensive, and time-consuming experimental determination of action patterns to crystal structures based energy calculations. Interaction energies between enzymes and carbohydrate substrates were calculated after short energy minimization by a molecular mechanics program. A training set of wild type and mutant amylases with known experimental action patterns of 13 enzymes of wide range of origin was used to set up the procedure. Calculations for training set resulted in good correlation in case of subsite binding energies (r2 = 0.827-0.929) and bond cleavage frequencies (r2 = 0.727-0.835). A set of eight novel barley amylase 1 mutants was used to test our model. Subsite binding energies were predicted with r2 = 0.502 correlation coefficient, while bond cleavage frequency prediction resulted in r2 = 0.538. Our computer-aided procedure may supplement the experimental subsite mapping methods to predict and understand characteristic features of alpha-amylases.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban alpha-amylase subsite mapping binding energy bond cleavage frequency molecular modeling
Megjelenés:	Carbohydrate Research. - 346 : 3 (2011), p. 410-415. -
További szerzők:	Gyémánt Gyöngyi (1960-) (vegyész) Harangi János (1950-) (biokémikus, kromatográfus) Bagossi Péter (1966-2011) (biokémikus, vegyész)
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