Alkaline inorganic pyrophosphatase from immature wheat grains

Kumar, Rakesh; Singh, Randhir

doi:10.1016/0031-9422(83)80128-9

Cited by 9 publications

(5 citation statements)

References 16 publications

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“…2C) as such does not offer a clear understanding on the involvement of this enzyme during starch accumulation in the seed of this legume. Our results are consistent with those obtained for wheat endosperm (Kumar and Singh 1983), suspension culture cells of soybean (Gross and apRees 1986) and developing pea embryos (Hylton and Smith 1992), where AGPase is sensitive to the inhibition by orthophosphate. The enzyme from wheat endosperm was insensitive to activation by 3-PGA and sensitive to the orthophosphate regulation (Gomez-Casati and Iglesias 2002) like the mung bean enzyme.…”

Section: Discussionsupporting

confidence: 95%

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Role of enzymes of sucrose-starch conversion in seed sink strength in mung bean

Chopra¹,

Kaur²,

Gupta³

2005

Biologia plant.

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Changes in the activities of sucrose synthase (SuSy), ADP-glucose pyrophosphorylase (AGPase), UDP-glucose pyrophosphorylase (UGPase), alkaline inorganic pyrophosphatase, 3-phosphoglycerate (3-PGA) phosphatase and amylases were monitored in relation to accumulation of starch in developing pods of mung bean (Vigna radiata L.). With the advancement in the seed development, the contents of starch rose with a concomitant fall in the branch of inflorescence and podwall after 10 d after flowering. The activity of UDPase in all the three pod tissues remained higher than the activity of AGPase showing it to be an important enzyme controlling carbon flux. The activity of alkaline inorganic pyrophosphatase in developing seed in contrast to 3-PGA phosphatase correlated with starch accumulation rate. Activity of β-amylase increased in all the pod tissues till maturity. It appears that the cooperative action of SuSy, UGPase and AGPase controls the efficient partitioning of sucrose into ADP glucose and thereby regulate the seed sink strength of the mung bean.Additional key words: alkaline inorganic pyrophosphatase, amylase, 3-PGA phosphatase, starch metabolism, sucrose synthase, Vigna radiata.

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Section: Discussionsupporting

confidence: 95%

“…The contents were incubated at 37 °C for 15 min. The liberated Pi was determined (Kumar and Singh 1983). For extracting 3-phosphoglycerate phosphatase 25 mM MES-KOH (pH 6.0) buffer was used.…”

Section: Methodsmentioning

confidence: 99%

Role of enzymes of sucrose-starch conversion in seed sink strength in mung bean

Chopra¹,

Kaur²,

Gupta³

2005

Biologia plant.

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“…Their results, summarized in Figure 1.4, indicate that the non-reducing sucrose reached a maximum level 14 days after anthesis, then declined and leveled off after 28 days. Starch synthesis FIGURE 1.3 Activity of alkaline inorganic pyrophosphatase (B) and ADPG-pyrophosphorylase (l) during wheat grain development (Kumar and Singh, 1983). was negligible after 7 days but increased markedly after 14 days, then continued until 35 days after anthesis.…”

Section: Sucrose Starch Conversion In Developing Grainsmentioning

confidence: 99%

Cereals and Legumes

Zhou

Slavin

Lutterodt

et al. 2013

Biochemistry of Foods

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“…The starch granules in the endosperm act as a major source of energy for the developing embryo (Zeleznak and Marston 1982), The amylases that catalyze the degradation of these granules are, however, synthesized in the pericarp-aleurone cells (Varner and Ho 1976), The next question, which arises in this context, is how a controlled degradation of starch occurs in the developing caryopsis, where the synthesis of this polymer is a predominant process. The production by amylases of hydrolysed products of starch for use as primers and/or for respiration during starch accumulation in cereal grain has been suggested (Kumar andSingh 1983b, Bhullar et al, 1985), A low recovery of amylases in whole caryopsis in comparison with endosperm (Tab, 3) seems to be a reflection of the presence of a variety of inhibitors of amylases in the pericarp-aleurone layer (Daiber 1975), A gradual decrease in the level and content of starch in bracts-pedicel with a concomitant rise in the associated caryopsis (Tiib. 1), indicates that the synthesis of starch in bracts is transitory and that they get depleted as the caryopsis increases in size.…”

Section: Distribution Of Amyiases In Caryopsismentioning

confidence: 99%

Import of sucrose and its transformation to starch in the developing sorghum caryopsis

Singh

Asthir

1988

Physiologia Plantarum

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Levels of soluble and bound invertases and amylases were studied in relation to the changes in the free sugars and the accumulation of starch in the developing sorghum [Sorghum bicolor (L.) Moench, cv. spv. 351] caryopsis and its associated bractspedicel. Besides sucrose, glucose and fructose as the principal sugars, small amounts of sugars of the raffinose series were detected in the developing caryopsis. Through out the period of caryopsis development, the amount of reducing sugars was higher than that of sucrose. With the advancement in the development of the caryopsis, the contents and levels of sucrose rose with a concomitant fall in the activity of soluble acid (pH 4.8) invertase (EC 3.2.1.26) in the endosperm. In the pericarp‐aleurone layer, the activity of soluble acid invertase predominated over soluble neutral (pH 7.5) invertase (EC 3.2.1.27). The activity of bound acid invertase declined with the ageing of the caryopsis. In bracts‐pedicel, the activity of bound invertase and the levels of reducing sugars peaked around 18 days post anthesis. In these organs, the level of starch gradually decreased concomitantly with an increase in its level in the developing caryopsis. Amylases (EC 3.2.1.1 and 3.2.1.2) are distributed in the endosperm as well as in the pericarp‐aleurone layer. On culturing detached ears in [U‐14C]‐sucrose solution for 6 h in the dark at 25°C, 80–90% of the 14C of extracted major sugars (i.e. sucrose + glucose + fructose) of the caryopsis appeared in sucrose alone. In comparison with the effects of glucose or fructose, transport into the caryopsis of 14C from [U‐14C]‐sucrose supplied to detached ears was promoted by the addition to the radiolabelled sucrose solution of 1% unlabelled sucrose. Addition to the [U‐14C]‐sucrose solution fed to the detached ears of 20 mM NaN3 or HgCl2 or galactose, lowered the amount of 14C in the free sugars and starch of the earyopsis.

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Alkaline inorganic pyrophosphatase from immature wheat grains

Cited by 9 publications

References 16 publications

Role of enzymes of sucrose-starch conversion in seed sink strength in mung bean

Role of enzymes of sucrose-starch conversion in seed sink strength in mung bean

Cereals and Legumes

Import of sucrose and its transformation to starch in the developing sorghum caryopsis

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