title: Effect of fatty acid interaction on myoglobin oxygen affinity and triglyceride metabolism.
abstract: Recent studies have suggested myoglobin (Mb) may have other cellular functions in addition to storing and transporting O2. Indeed, NMR experiments have shown that the saturated fatty acid (FA) palmitate (PA) can interact with myoglobin (Mb) in its ligated state (MbCO and MbCN) but does not interact with Mb in its deoxygenated state. The observation has led to the hypothesis that Mb can also serve as a fatty acid transporter. The present study further investigates fatty acid interaction with the physiological states of Mb using the more soluble but unsaturated fatty acid, oleic acid (OA). OA binds to MbCO but does not bind to deoxy Mb. OA binding to Mb, however, does not alter its O2affinity. Without any Mb, muscle has a significantly lower level of triglyceride (TG). In Mb knock-out (MbKO) mice, both heart and skeletal muscles have lower level of TG relative to the control mice. Training further decreases the relative TG in the MbKO skeletal muscle. Nevertheless, the absence of Mb and lower TG level in muscle does not impair the MbKO mouse performance as evidenced by voluntary wheel running measurements. The results support the hypothesis of a complex physiological role for Mb, especially with respect to fatty acid metabolism.
authors.affiliation: Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA. TJue@ucdavis.edu.
authors.forename: Thomas
authors.identifier: http://orcid.org/0000-0003-1549-8414
authors.initials: T
authors.lastname: Jue
authors.affiliation: Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Simond
authors.affiliation: Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX, 77843, USA.
authors.forename: Traver J
authors.initials: TJ
authors.lastname: Wright
authors.affiliation: Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA.
authors.forename: Lifan
authors.initials: L
authors.lastname: Shih
authors.affiliation: Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA.
authors.forename: Youngran
authors.initials: Y
authors.lastname: Chung
authors.affiliation: Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA.
authors.forename: Renuka
authors.initials: R
authors.lastname: Sriram
authors.affiliation: Department of Biochemistry and Molecular Medicine, University of California Davis, Davis, CA, 95616-8635, USA.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Kreutzer
authors.affiliation: Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX, 77843, USA.
authors.forename: Randall W
authors.initials: RW
authors.lastname: Davis
mesh_terms: D000818:Animals; D006736:Horses; D050356:Lipid Metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D009211:Myoglobin / Q000737:chemistry / Q000378:metabolism*; D019301:Oleic Acid / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D014280:Triglycerides / Q000378:metabolism*
chemical_list: D009211:Myoglobin; D014280:Triglycerides; D019301:Oleic Acid
keywords: Bioenergetics; Fatty acid; Lipid; Metabolism; NMR