УДК 634.11:581.19

DYNAMICS VARIATIONS OF KINETIC PROPERTIES OF NADF-DEPENDENT ISOCITRATE DEHYDROGENASE DURING APPLE FRUITS RIPENING

Sabina Novruz Omarova, Yashar Adil’ Omarov, Ziyaddin Makhmud Mamedov, Akif Alekper Kuliev

The authors studied the changes in activity and kinetic properties of NADP-dependent isocitrate dehydrogenase (NADP-IDG) from subepidermal tissue of apple fruits during afterripening. It was revealed, that the increasing of enzyme activity by 28 % accompanies the fruits ripening. The ions of Mn2+ and Mg2+ activate, however, an enzyme affinity to Mg2+ and therefore the degree of its activation in the presence this cation was higher. The enzyme manifests the Michaelis-Menten kinetics. The value of Km for enzyme from preclimacteric and climacteric fruits for NADP, isocitrate and Mg2+ differ negligible. GTP, ATP and UTP in the complex with Mg2+ inhibit the activity of NADP-IDG at both stages of ripening, but in process of ripening their inhibitory action decline. The appropriate nucleotide diphosphates activate the NADP-IDG and their effect intensified on later stages of ripening.

Keywords: NADP+-isocitratedehydrogenase, fruit ripening, apples, bivalent cations, nucleoside phosphates.

Бакинский государственный университет,
Республика Азербайджан, АZ-1148, г. Баку,
ул. Академика З. Халилова, 23,
e-mail: saboma@rambler.ru, biochem@mail.az

Поступила в редакцию
12 мая 2009 года

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