Partial purification of tightly bound mitochondrial hexokinase from maize (Zea mays L) root membranes
Braz. j. med. biol. res
;
39(9): 1159-1169, Sept. 2006. graf, tab
Artigo
em Inglês
| LILACS
| ID: lil-435432
ABSTRACT
In mammals, hexokinase (HK) is strategically located at the outer membrane of mitochondria bound to the porin protein. The mitochondrial HK is a crucial modulator of apoptosis and reactive oxygen species generation. In plants, these properties related to HK are unknown. In order to better understand the physiological role of non-cytosolic hexokinase (NC-HK) in plants, we developed a purification strategy here described. Crude extract of 400 g of maize roots (230 mg protein) contained a specific activity of 0.042 æmol G6P min-1 mg PTN-1. After solubilization with detergent two fractions were obtained by DEAE column chromatography, NC-HK 1 (specific activity = 3.6 æmol G6P min-1 mg PTN-1 and protein recovered = 0.7 mg) and NC-HK 2. A major purification (yield = 500-fold) was obtained after passage of NC-HK 1 through the hydrophobic phenyl-Sepharose column. The total amount of protein and activity recovered were 0.04 and 18 percent, respectively. The NC-HK 1 binds to the hydrophobic phenyl-Sepharose matrix, as observed for rat brain HK. Mild chymotrypsin digestion did not affect adsorption of NC-HK 1 to the hydrophobic column as it does for rat HK I. In contrast to mammal mitochondrial HK, glucose-6-phosphate, clotrimazole or thiopental did not dissociate NC-HK from maize (Zea mays) or rice (Oryza sativa) mitochondrial membranes. These data show that the interaction between maize or rice NC-HK to mitochondria differs from that reported in mammals, where the mitochondrial enzyme can be displaced by modulators or pharmacological agents known to interfere with the enzyme binding properties with the mitochondrial porin protein.
Texto completo:
DisponíveL
Índice:
LILACS (Américas)
Assunto principal:
Raízes de Plantas
/
Zea mays
/
Hexoquinase
/
Mitocôndrias
Limite:
Animais
Idioma:
Inglês
Revista:
Braz. j. med. biol. res
Assunto da revista:
Biologia
/
Medicina
Ano de publicação:
2006
Tipo de documento:
Artigo
/
Documento de projeto
País de afiliação:
Brasil
/
Espanha
Instituição/País de afiliação:
Universidad de Barcelona/ES
/
Universidade Estadual do Norte Fluminense/BR
/
Universidade Federal do Rio de Janeiro/BR
Similares
MEDLINE
...
LILACS
LIS