of sucrose synthase from thermotolerant wheat grains and its characterization
Verma, B. Sharma*, H.R. Singal and R. Munjal
Chemistry and Biochemistry, Department of Genetics and Plant Breeding,? CCS,
Haryana Agricultural University, Hisar-125 004, India
Author E-mail: email@example.com
Paper received : 02.11.2016
Revised received : 14.07.2017
Re-revised received :
Accepted : 07.11.2017?? ???
Aim: Wheat is common
and popular cereal with wide utilization and acceptability. High temperature
stress drastically affects crop productivity and quality by disturbing
sucrose metabolism. Hence, the aim of present investigation was to purify and
characterize of sucrose synthase from thermotolerant wheat for various
physico-chemico-kinetic properties. ???
immature grains of thermotolerant wheat WH-1021 were used for purification of
sucrose synthase by using traditional protein purification techniques viz.
(NH4)2SO4 fractionation, gel filtration through sephadex G-100 and
DEAE-cellulose ion exchange chromatography. The purity was checked by native
PAGE, while subunit by SDS PAGE. ???????
Results: The enzyme was purified about 27 fold with
approximately 37% recovery. The native enzyme had a molecular weight of 269
KDa and subunit molecular weight was found to be 63 KDa, indicating that
enzyme is a homotetramer. The purified enzyme exhibited optimum activity at
37?C with thermostablity upto 50?C and pH 6.5. Sucrose
synthase showed Km values of 14.28 and 1.18 mM for sucrose and UDP,
respectively. Its activity was inhibited by Mn2+ (38.5%), while NO3-
stimulated the activity by 20.8% at 2 mM concentration. ?????
the various nucleotides tested, the enzyme was highly specific for UDP as
substrate and NADP+ and G-6-P were found to be the potent
inhibitors. The kinetic studies revealed that sucrose synthase catalyzed the
sucrose degradation by ping-pong mechanism. The results of the present study
would help in planning the strategies for increased wheat productivity
without compromising the quality under stress conditions.
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