Uptake and metabolism of (14C)-aspartate by developing kernels of maize (Zea mays L. )
Abstract
Pulse-chase experiments were performed to determine the metabolic fate of (14C)-aspartate in the pedicel region and subsequent uptake into the endosperm. Kernels were removed from the cob, leaving the pedicel attached but removing glumes, palea, and lemma. The basal tips were incubated in (14C)-aspartate for 0.5 h, followed by a 2 h chase period with unlabeled aspartate. In contrast to a previous study in which 70% of the 14C from aspartate was recovered in the organic acid fraction (Lyznik, et al., Phytochemistry 24: 425, 1985), only 20 to 25% of the radioactivity found in the 2 h chase period. While a small amount of the 14C transiently appeared in alanine at the beginning of the chase period, the most heavily labeled non-fed amino acid was glutamine, which accounted for 21% of the radioactivity within the pedicel amino acid fraction by 0.5 h into the chase period. There was no evidence for asparagine synthesis within the pedicel region of the kernel. 14C recovered from the endosperm in the form of amino acids were aspartate (60%), glutamine (20%), glutamate (15%), and alanine (5%). These results suggest that some of the maternally supplied amino acids undergo metabolic conversion to other amino acids beforemore »
- Authors:
-
- USDA, Peoria, IL (USA)
- Publication Date:
- OSTI Identifier:
- 5627750
- Report Number(s):
- CONF-9007196-
Journal ID: ISSN 0079-2241; CODEN: PPYSA
- Resource Type:
- Conference
- Journal Name:
- Plant Physiology, Supplement; (USA)
- Additional Journal Information:
- Journal Volume: 93:1; Conference: Annual meeting of the American Society of Plant Physiologists, Indianapolis, IN (USA), 29 Jul - 2 Aug 1990; Journal ID: ISSN 0079-2241
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 59 BASIC BIOLOGICAL SCIENCES; AMINO ACIDS; BIOLOGICAL PATHWAYS; ASPARTIC ACID; METABOLISM; UPTAKE; CARBON 14 COMPOUNDS; MAIZE; TRACER TECHNIQUES; CARBOXYLIC ACIDS; CEREALS; GRAMINEAE; ISOTOPE APPLICATIONS; LABELLED COMPOUNDS; LILIOPSIDA; MAGNOLIOPHYTA; ORGANIC ACIDS; ORGANIC COMPOUNDS; PLANTS; 550501* - Metabolism- Tracer Techniques
Citation Formats
Muhitch, M J. Uptake and metabolism of (14C)-aspartate by developing kernels of maize (Zea mays L. ). United States: N. p., 1990.
Web.
Muhitch, M J. Uptake and metabolism of (14C)-aspartate by developing kernels of maize (Zea mays L. ). United States.
Muhitch, M J. 1990.
"Uptake and metabolism of (14C)-aspartate by developing kernels of maize (Zea mays L. )". United States.
@article{osti_5627750,
title = {Uptake and metabolism of (14C)-aspartate by developing kernels of maize (Zea mays L. )},
author = {Muhitch, M J},
abstractNote = {Pulse-chase experiments were performed to determine the metabolic fate of (14C)-aspartate in the pedicel region and subsequent uptake into the endosperm. Kernels were removed from the cob, leaving the pedicel attached but removing glumes, palea, and lemma. The basal tips were incubated in (14C)-aspartate for 0.5 h, followed by a 2 h chase period with unlabeled aspartate. In contrast to a previous study in which 70% of the 14C from aspartate was recovered in the organic acid fraction (Lyznik, et al., Phytochemistry 24: 425, 1985), only 20 to 25% of the radioactivity found in the 2 h chase period. While a small amount of the 14C transiently appeared in alanine at the beginning of the chase period, the most heavily labeled non-fed amino acid was glutamine, which accounted for 21% of the radioactivity within the pedicel amino acid fraction by 0.5 h into the chase period. There was no evidence for asparagine synthesis within the pedicel region of the kernel. 14C recovered from the endosperm in the form of amino acids were aspartate (60%), glutamine (20%), glutamate (15%), and alanine (5%). These results suggest that some of the maternally supplied amino acids undergo metabolic conversion to other amino acids before being taken up by the endosperm.},
doi = {},
url = {https://www.osti.gov/biblio/5627750},
journal = {Plant Physiology, Supplement; (USA)},
issn = {0079-2241},
number = ,
volume = 93:1,
place = {United States},
year = {Tue May 01 00:00:00 EDT 1990},
month = {Tue May 01 00:00:00 EDT 1990}
}