Data/hora: 18/06/2024 18:06:37

Biblioteca(s): | Embrapa Mandioca e Fruticultura.
Data corrente: | 21/08/1995
Data da última atualização: | 21/08/1995
Autoria: | KRUGER, I.; KLUGE, M.
Afiliação: | Institut fur Botanik der Technischen Hochschule Darmstadt, FRG.
Título: | Diurnal changes in the regulatory properties of phosphoenolpyruvate carboxylase in CAM plants: are alterations in the quaternary structure involved?
Ano de publicação: | 1988
Fonte/Imprenta: | Botanica Acta, v.101, p.32-35, 1988
Idioma: | Inglês
Conteúdo: | Day- and night-forms of phosphoenolpyruvate carboxylase (EC 4.1.1.3.1) (PEP-C) were extracted from leaves of the CAM plant Kalanchoe daigremontiana. During storage after extraction, the day-form spontaneously lost its sensitivity towards the allosteric inhibitor L-malate. This effect was accelerated by inorganic phosphate, PEP, 3-PGA and G-6-P.L-Malate however stabilized the malate sensitivity of the day-form of PEP-C. Crude desalted extwracts of the day-form and of the night-form of PEP-C were subjected to ultracentrifugation on a continuous sucrose gradient in the presence of malate and to marker enzymes. Both forms of PEP-C were foud to haver relative molecular masses of about 200,000. This suggests that both forms represent the dimers of the enzyme protein. The result also suggests that reversible dissociation and association of enzyme subunits is not the mechanism which brings about the interconversion of the two PEP-C forms during the diurnal CAM cycle in vivo.
Palavras-Chave: | Kalanchoe daigremontiana; PEP-carboxylase; Quaternary structyre; Regulation.
Thesaurus Nal: | Crassulacean acid metabolism.
Categoria do assunto: | --
Registro original: | Embrapa Mandioca e Fruticultura (CNPMF)
Exemplares: | CNPMF - (15840-1) - ADC - SP - -- - S5155 -  - S5155 - DIS