Effects of free Ca²⁺ on kinetic characteristics of holotransketolase

Autor:	Olga N, Solovjeva, Irina A, Sevostyanova, Vladimir A, Yurshev, Vitalii A, Selivanov, German A, Kochetov
Rok vydání:	2012
Předmět:	Kinetics Pentosephosphates Saccharomyces cerevisiae Proteins Osmolar Concentration Calcium Dextrans Ribosemonophosphates Saccharomyces cerevisiae Thiamine Pyrophosphate Transketolase Holoenzymes
Zdroj:	The protein journal. 31(2)
ISSN:	1875-8355
Popis:	Catalytic activity has been demonstrated for holotransketolase in the absence of free bivalent cations in the medium. The two active centers of the enzyme are equivalent in both the catalytic activity and the affinity for the substrates. In the presence of free Ca²⁺ (added to the medium from an external source), this equivalence is lost: negative cooperativity is induced on binding of either xylulose 5-phosphate (donor substrate) or ribose 5-phosphate (acceptor substrate), whereupon the catalytic conversion of the bound substrates causes the interaction between the centers to become positively cooperative. Moreover, the enzyme total activity increase is observed.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=pmid________::f83840e7cb4a60f6e58470f32e9b01a2 https://pubmed.ncbi.nlm.nih.gov/22210509 Zobrazit plný text záznamu Full text from SpringerLink