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In vivo phosphorylation of phosphofructokinase at a novel site

This thesis examines the interconnection between the in vitro and in
vivo phosphorylation of rabbit muscle phosphofructokinase. The first goal
of the project was to show whether a novel site of rabbit muscle
phosphofructokinase that is subject to in vitro phosphorylation, serine 376,
may also become phosphorylated in vivo. Evidence obtained through iron
chelate chromatography, amino acid analysis, gas phase sequencing,
ammonium sulfate reversed phase high pressure liquid chromatography
(HPLC), and matrix-assisted laser desorption/ ionization time-of-flight
(MALDI-TOF) spectroscopy of cyanogen bromide digests of the enzyme
purified from epinephrine-stimulated rabbit hearts demonstrate the in vivo
phosphorylation of serine 376. Parallel experiments with
phosphofructokinase isolated from unstimulated rabbit hearts show no
detectable phosphorylation of serine 376.
The second part of the thesis examines the effects of alterations in
experimental conditions on the in vitro phosphorylation of rabbit muscle
phosphofructokinase that is catalyzed by the cAMP-dependent protein
kinase (cAMP-dPK). Significant phosphorylation of serine 376 takes place
in the presence of specific proteins, calmodulin-calcium and troponin C-calcium,
that are known to stabilize the catalytically inactive
phosphofructokinase dimer. Conditions that stabilize the catalytic activity
of phosphofructokinase generally inhibit the in vitro phosphorylation
reaction. / Graduation date: 1999

Identiferoai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/33481
Date08 April 1999
CreatorsHarrahy, John J.
ContributorsAnderson, Sonia R.
Source SetsOregon State University
Languageen_US
Detected LanguageEnglish
TypeThesis/Dissertation

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