The Relationship between Pyrophosphatase and Branching Enzyme Activity with Amyloplast Size in Maize Endosperm

• Published in: Journal of plant physiology Vol. 146; no. 1; pp. 41 - 46
• Main Authors: Zamski, Eli, Liu, Kang-Chien, Shannon, Jack C.
• Format: Journal Article
• Language: English
• Published: Jena Elsevier GmbH 1995; Elsevier
• Subjects: ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; ALMIDON; AMIDON; Amyloplast; Amyloplasts; Biochemie; Biological and medical sciences; branching enzyme; CARBOHYDRATE METABOLISM; ENDOSPERM; ENDOSPERMA; ENDOSPERME; ENZIMAS; Enzymaktivitaet; ENZYME; ENZYMES; ENZYMIC ACTIVITY; Fundamental and applied biological sciences. Psychology; GRAINE; Kohlenhydratstoffwechsel; maize; Metabolism; METABOLISME DES GLUCIDES; METABOLISMO DE CARBOHIDRATOS; Pflanzenbau; Photosynthesis, respiration. Anabolism, catabolism; Plant physiology and development; PLASTE; PLASTIDIOS; PLASTIDS; Pyrophosphatase; Samen; SEEDS; SEMILLA; Staerke; STARCH; Zea; ZEA MAYS; FW; DAP; BE; ADH; branching enzyme; starch; Amyloplasts; maize; pyrophosphatase; PPase; sup; Monocotyledones; Zea mays; Enzyme; Transferases; Glycosyltransferases; Amyloplast; Cereal crop; 1,4-α-Glucan branching enzyme; Enzymatic activity; Gramineae; Angiospermae; Development; Hexosyltransferases; Spermatophyta; Endosperm; Caryopsis; Pyrophosphatase
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1016/S0176-1617(11)81965-6

This study aimed to clarify the relationship between amyloplast size (age) and activities of alkaline pyrophosphatase (PPase) and branching enzyme (BE) within developing
Zea mays L. endosperm cells. PPase and BE activities per starch granule were increased when the organelle grew in size, although decreased when calculated per granule surface area. The amyloplast specific PPase and the stromal marker enzyme BE had identical distribution (percent of total activity) in the stroma. The amount of free Pi increased in the stroma with the increased granule size up to 8 μ in diameter (about one third of the final size) and then remained steady. The maximum Pi content at this granule size was 5.2 mmol per 10
6 amyloplasts (about 5.5 fmol per granule) and PPase activity released about 1 nmol min
-1 per 10
6 amyloplasts. Attempts to detect endogenous PPi in amyloplasts were unsuccessful.