Factors Influencing Diamine Oxidase Activity and γ-Aminobutyric Acid Content of Fava Bean (Vicia faba L.) during Germination

Abstract

Factors (germination time, spectra, temperature, pH, and chemical inhibitors) influencing diamine oxidase (DAO, EC 1.4.3.6) activity and γ-aminobutyric acid (GABA) content of fava bean (Vicia faba L.) during germination were investigated in this study. DAO activity significantly increased in germinating seeds but varied with different organs. The enzyme activity was higher in shoot than that in cotyledon, hypocotyl, and radicle. When seeds were germinated in the dark, DAO activity was 2.35-, 2.00-, 2.36-, 4.40-, and 1.67-fold of that under white, red, blue, green, and yellow spectra, respectively. The optimum germination temperature and pH value for increasing DAO activity were 30 °C and 3.0, respectively. The DAO activity was inhibited significantly by aminoguanidine and sodium ethylenediamine tetracetate, while it was activated by CuCl(2) and CaCl(2). Germinating at an appropriate temperature and pH, 30% of GABA formation was supplied by DAO. Calcium was related to the regulation of DAO activity and GABA accumulation.

Sequence analysis of diamine oxidase gene from fava bean and its expression related to γ‐aminobutyric acid accumulation in seeds germinating under hypoxia‐NaCl stress

“…Xing et al showed that the polyamine degradation pathway could supply 39% of GABA accumulation in NaCl‐treated soybean root. In the present study the contribution of the polyamine degradation pathway to GABA accumulation in the cotyledon and shoot (under hypoxia, 28.14 and 21.86% respectively; under hypoxia‐NaCl, 31.13 and 22.76% respectively) coincided with that of previous reports . However, the GABA content in the radicle was not affected by AG.…”

“…Hence AG only inhibited a part of GABA formation. We previously detected that the polyamine degradation pathway supplied about 30% of GABA accumulation in germinating fava bean under non‐stress or hypoxia condition . Xing et al showed that the polyamine degradation pathway could supply 39% of GABA accumulation in NaCl‐treated soybean root.…”

“…GABA was extracted and purified according to Bai et al The residue was dissolved in 2 mL of 1 mol L −1 sodium bicarbonate (pH 9) and centrifuged at 6000 × g for 10 min. GABA content was determined using an Agilent 1200 Series HPLC system with a ZORBAX Eclipse AAA reverse phase column (150 mm × 4.6 mm i.d., 3.5 µm; Agilent, Palo Alto, Calif., USA) as described by Yang et al …”

Activity of some isoenzymatic systems in stored coffee grains

“…Moreover, the grain deterioration is a continuous process of physiological and biochemical causes related to the seed metabolism, which may lead to the denaturation of enzymes (Taiz;Zeiger, 2004), affecting the efficiency of protection on the membrane phospholipids (Carvalho, et al, 2006;Henning et al 2009), thus generating toxic compounds (Dussert et al, 2006), allowing the higher production of leached (Santos et al, 2004;Vidigal et al, 2009;Veiga et al, 2010). This is in accordance to Yang, Chen and Gu (2011), who suggests that stress can promote oxidation the enzymes in the seeds stored.…”

Hypoxia treatment on germinating faba bean (Vicia faba L.) seeds enhances GABA-related protection against salt stress

“…The GAD activity of plant tissues is defined as 1 mg protein units of GAD activity. The DAO activity was determined according to Yang et al (2011a). A 0.01 value of the changes per minute in absorbance at 555 nm was regarded as one unit of enzyme activity.…”