Amino acid catabolism by ribbed mussel (Modiolus demissus) gill tissue: studies on isolated mitochondria and the L-amino acid oxidase

dc.contributor.author Burcham, James
dc.contributor.department Zoology
dc.date 2018-08-15T17:32:24.000
dc.date.accessioned 2020-07-02T06:07:01Z
dc.date.available 2020-07-02T06:07:01Z
dc.date.copyright Sat Jan 01 00:00:00 UTC 1983
dc.date.issued 1983
dc.description.abstract <p>Gill tissue from Modiolus demissus has a general L-amino acid oxidase (EC 1.4.3.2) associated with proteinaceous particles sedimenting at 15,000xg. The oxidase is most active between pH 4.5 and pH 5 in citrate buffer with L-(alpha)-amino acids having three or more carbons, with no hydroxyl or methyl substitutions for hydrogens on the (beta)-carbons, and no charged groups on the (gamma)-carbon. The apparent K(,m)s for L-leucine and L-ornithine were identical (2.5 mM). Glycine, taurine, L-proline, aminooxyacetic acid, L-cycloserine, and EDTA would not act as substrates or inhibitors;Preliminary experiments with 2,4-dinitrophenol (DNP), 2,4,6-trinitrophenol (TNP), and sodium azide indicated that most of the oxygen consumption by ribbed mussel gill tissue was the result of mitochondrial respiration. A procedure utilizing isoosmotic sucrose, EGTA, defatted serum albumin, and HEPES as the isolation medium was devised for the preparation of fully coupled ribbed mussel gill mitochondria. Optimal rates of respiration and respiratory coupling required substrate, ADP, inorganic phosphate and a fairly high KC1 concentration (90 mM) in the assay medium. Preparation of gill mitochondria in isoosmotic solutions containing high KC1 concentrations (150 mM) yielded mitochondria with state 2 respiration, partially uncoupled ATP synthesis during state 3 respiration and no state 4 respiration;The presence of arginase, ornithine aminotransferase, P-5-C reductase, and proline oxidase was demonstrated in gill tissue from the ribbed mussel, Modiolus demissus. Ornithine aminotransferase and proline oxidase were found in mitochondrial fractions, and indirect evidence is presented for a mitochondrial P-5-C dehydrogenase. The proline oxidase lost its rotenone sensitivity in mechanically disrupted metochondria but retained sensitivity to antimycin A. The apparent K(,m)'s for partially purified arginase and ornithine aminotransferase were 7 mM for arginine and 4.8 mM and 2 mM for ornithine and 2-oxoglutarate, respectively. Amino acid analysis and radiotracer experiments indicated that at low concentrations proline is catabolized primarily to glutamate, organic acids and CO(,2).</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/rtd/8456/
dc.identifier.articleid 9455
dc.identifier.contextkey 6335085
dc.identifier.doi https://doi.org/10.31274/rtd-180813-8560
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath rtd/8456
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/81446
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/rtd/8456/r_8407055.pdf|||Sat Jan 15 02:11:44 UTC 2022
dc.subject.disciplines Agriculture
dc.subject.disciplines Animal Sciences
dc.subject.disciplines Aquaculture and Fisheries
dc.subject.disciplines Zoology
dc.subject.keywords Zoology
dc.title Amino acid catabolism by ribbed mussel (Modiolus demissus) gill tissue: studies on isolated mitochondria and the L-amino acid oxidase
dc.type article
dc.type.genre dissertation
dspace.entity.type Publication
thesis.degree.level dissertation
thesis.degree.name Doctor of Philosophy
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