• BMB Reports
• /
• 제28권2호
• /
• pp.100-106
• /
• 1995

S-adenosylmethionine (SAM) synthetase was purified to homogeneity from soybean (Glycine max) axes. The enzyme was purified 216-fold with a 1.5% yield by ammonium sulfate fractionation, acetone fractionation, ion exchange chromatography with DEAE-sephacel, gel filtration with Sephacryl S-300, and afffinity chromatography with ATP-agarose. The enzyme activity reached a maximum 3 days after germination. SAM synthetase had a subunit molecular weight of 57,000 daltons from a silver stained single band on SDS-PAGE. The molecular weight of the enzyme was 110,000 daltons from Sephacryl S-300 gel filtration. The enzyme was composed of two identical subunits. The $K_m$ values of the enzyme for L-methionine and ATP were 1.81 and 1.53 mM, respectively. The enzymatic activity was not affected by polyamines, agmatine, or SAM analogues, but was inhibited by SAM. The inhibition pattern was showed non-competitive for L-methionine and uncompetitive for ATP. The activity of SAM synthetase was inhibited by thiol-blocking reagents. The enzyme was induced by treatment with $10^{-3}$ M putrescine at germination. Experimental data revealed a possible novel regulation mechanism of polyamine biosynthesis through several endogenous intermediates.

• 한국작물학회지
• /
• 제44권2호
• /
• pp.129-133
• /
• 1999

Excessive soil water at vegetative growth stages during the rainy season induces yield losses in soybeans. Our objectives were to obtain basic information about the cultivar differences and to understand the stress-tolerance process for due to excessive soil water. Previous experiments revealed soybean genotypic differences in tolerance to excessive soil water. A field experiment was conducted at the Research Farm of Korea University near Seoul on 21 May 1998. Soybean[Glycine max (L.) Merrill] cultivars, 'Hannamkong' (sensitive) and 'Taekwan-gkong'(tolerant) were planted in vinyl-lined plots(1.2 x 4.2 x 0.3 m deep) and control plots. Drip irrigation began at VI growth stage to submerge the soil surface. Three weeks of excessive soil water treatment reduced all growth parameters measured to soybean plants. Excessive soil water stress resulted in decreases of N, P, K, Ca, Mg and Cu, and increases of Fe and Mn contents in soybean leaves. The stress index of tolerant cultivars under excessive soil water showed no large difference in soybean growth characteristics measured at three growth stages. However, K, Ca, Mg, Fe and Mn contents in soybean leaves appeared to differ between sensitive and tolerant cultivars. From the above results, stress and tolerance indices are proposed for a method to test cultivar differences in plant responses within a species under adverse growth environments.

• 한국미생물·생명공학회지
• /
• 제14권2호
• /
• pp.187-192
• /
• 1986

대두근류균 접종제 개발을 목적으로 수집 분리되어 우수균주로 선발된 근류균(Rhizobium japonicum)을 대상으로 가기 재배경력이 상이한 3종류의 토양에 장엽콩을 공시 품종으로 하여 접종효과 시험을 실시하였다. 그 결과 근류형성정도 및 질소고정활성을 보면 근류균무접종구에 비하여 근류균을 접종함으로써 3토양 모두 현저한 근류형성 및 질소고정활성의 증가를 보였고 그에 따라 대두의 생육정도도 양호하여 평균 10％의 건물중의 증가를 보였다. 토양별 총질소고정활성의 증가지수는 개간전토양 238％. 미숙전토양 266％, 숙전토땅 157％로 개간전 및 미숙전토양에서 접종효과가 뚜렷하였다. 공시 근류균주별 접종효과는 Rhizobium japonicum R-214, R-138 균주가 우수한 접종효과를 나타냈다.