Gibberellic Acid-Enhanced Synthesis and Excretion of Phosphatase lsozymes by Embryoless Rice Seeds

Suzuki, Shoho; Nakamura, Saheye; Nisizawa, Kazutosi

doi:10.15281/jplantres1887.83.82

Cited by 3 publications

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“…It was essentially constant after 4 days of germination. Phytase is probably a different enzyme from phosphomonoesterase since acid phosphatase of embryoless seed halves treated with GA. has been reported to have very low specificity for phytin (24). Specific activity of phytase has also been reported to increase during rice germination in the dark (15).…”

Section: Resutltsmentioning

confidence: 99%

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Changes in the Activity of Some Hydrolases, Peroxidase, and Catalase in the Rice Seed during Germination

Palmiano

Juliano²

1973

Plant Physiol.

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A study was made of the changes in activity of enzymes involved in the breakdown of stored phytin, lipid, and hemicellulose in the aleurone layer of rice seed (Oryza sativa L., variety 1R8) during the 1st week of germination in the light. Enzyme assays were made on crude extracts from degermed seed, and activities were expressed on a per seed basis. Phytase activity increased within the 1st day of germination. The increase in activity of most other enzymes-phosphomonoester. ase, phosphodiesterase, esterase, lipase, peroxidase, catalase, 5-glucosidase, and a-and~-galactosidase-closely followed the increase in protein content. Their peak activities occurred by the 5th to the 7th day. Some enzymes, such as 5-1,3-glucanase and a-amylase, continued to increase in activity after the 7th day. Phytase, L-1 ,3-glucanase, and a-amylase followed a similar sequence of production in embryoless seed halves incubated in 0.12 AM gibberellin A3, but the production of lipase was delayed.The aleurone layer of cereals is the site of production of hydrolases during seed germination and during incubation of embryoless seed halves or isolated aleurone layers in GA3 (2, 6-8, 19, 21, 24). Many hydrolases have been studied, including a-amylase (2, 19), protease (6,19), phytase (10, 15), phosphatase (24), lipase (26), and RNase (2,19). Phytase has been shown to be located in the protein bodies of the barley aleurone layers (17).The aleurone layer of rice (Oryza sativa L.) is a storage organ for phosphate in the form of phytin (9, 15) and for lipids (12); it is richer in hemicellulose than the endosperm (4). It is devoid of starch granules in the mature grain (9). Jones (8) Enzyme Extraction. Ten degermed dehulled grains were homogenized at 0 to 4 C at top speed in a VirTis 45 homogenizer for 3 min with 10 ml of 0.1 M tris-HC1 buffer (pH 7.0). The homogenate was centrifuged at 30,000g for 10 min at 4 C, and the crude enzyme was used for the assays, except for assays of lipase and /3-1 ,3-glucanase, which were done on the protein fraction of the crude enzyme precipitating between 0 and 80% saturation with (NH4)2S04. Soluble protein was determined by the Folin phenol reagent (11) corrected for the reading of the tris buffer.Phosphatases and Esterases. The method of Pollard (21) using p-nitrophenyl derivatives was used for the assay of phosphomonoesterase, phosphodiesterase, and esterase. The incubation mixture consisted of the crude extract of degermed seed and substrate equivalent to 0.5 ZImole of p-nitrophenol (mono-phosphate, bisphosphate, and acetate) in 0.1 M acetate buffer (pH 5.0) at 30 C. Incubation time was 15 min for phosphatases and 1 hr for esterase. To stop the reaction, Na,C03 was added, and the amount of p-nitrophenol released was determined colorimetrically at 420 nm. Activities were expressed in ,tmoles of p-nitrophenol formed per hour per seed.Phytase activity was assayed by the method of Mukherji et al. (15) except that incubation time was only 15 min at 30 C at pH 4.0. The amount of phosphate released was measure...

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Section: Resutltsmentioning

confidence: 99%

“…Many hydrolases have been studied, including a-amylase (2, 19), protease (6,19), phytase (10, 15), phosphatase (24), lipase (26), and RNase (2, 19). Phytase has been shown to be located in the protein bodies of the barley aleurone layers (17).…”

mentioning

confidence: 99%

Changes in the Activity of Some Hydrolases, Peroxidase, and Catalase in the Rice Seed during Germination

Palmiano

Juliano²

1973

Plant Physiol.

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show abstract

Changes in the patterns of phosphatase isozymes during the germination of rice seed

Suzuki¹,

Nisizawa²

1974

Bot Mag Tokyo

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Einfluß von Gibberellinsäure auf die Phosphohydrolasen keimender Embryonen von Triticum aestivum L.1)1)Herrn Professor Dr. Dr. mult. h. c. Kurt Mothes zum 75. Geburtstag gewidmet.

Völksch¹,

Augsten²

1975

Biochemie und Physiologie der Pflanzen

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Gibberellic Acid-Enhanced Synthesis and Excretion of Phosphatase lsozymes by Embryoless Rice Seeds

Cited by 3 publications

References 0 publications

Changes in the Activity of Some Hydrolases, Peroxidase, and Catalase in the Rice Seed during Germination

Changes in the Activity of Some Hydrolases, Peroxidase, and Catalase in the Rice Seed during Germination

Changes in the patterns of phosphatase isozymes during the germination of rice seed

Einfluß von Gibberellinsäure auf die Phosphohydrolasen keimender Embryonen von Triticum aestivum L.1)1)Herrn Professor Dr. Dr. mult. h. c. Kurt Mothes zum 75. Geburtstag gewidmet.

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