Characterization of glycoprotein antifreeze biosynthesis in isolated hepatocytes from Pagothenia borchgrevinki

Journal Article · Sat Apr 10 04:00:00 EST 1982 · J. Exp. Zool.; (United States)

DOI:https://doi.org/10.1002/jez.1402200207· OSTI ID:7056397

O'Grady, S M; Clarke, A; DeVries, A L

Incorporation of /sup 14/C-leucine and /sup 3/H-alanine into TCA-precipitable protein. TCA-soluble protein, and antifreeze glycoproteins (AFGP) was measured in isolated hepatocytes from Pagothenia borchgrevinki Boulenger following acclimation to -1.5 degrees C and +4 degrees C. the rate of /sup 3/H-alanine incorporation into AFGP followed Michaelis-Menten kinetics with a Vmax of 4.8 nM X mg protein-1 X h-1 at -1.5 degrees C and 7.5 nM X mg protein-1 X h-1 at +4 degrees C. Km values were 27.9 microM and 41.7 microM at -1.5 degrees C and +4 degrees C, respectively. Incorporation of /sup 14/C-leucine into TCA-precipitable protein also showed Michaelis-Menten kinetics with a Vmax of 20 nM X mg protein-1 X hr-1 at 1.5 degrees C and 32.3 nM X mg protein-1 X hr-1 at +4 degrees C. Km values were 83.3 microM at -1.5 degrees C and 125 microM at +4 degrees C. AFGP synthesis was monitored over a 120-h period by radioimmunoassay in cultures of hepatocytes from cold acclimated fish (-1.5 degrees C) incubated at both -1.5 degrees C and +4 degrees C. The estimated Q10 for AFGP from these data is 3.23. Polyacrylamide gel electrophoresis of antifreeze glycoproteins produced by isolated hepatocytes showed that all four antifreeze fractions normally present in the serum of P. borchgrevinki are also synthesized by isolated hepatocytes. The two major conclusions from these experiments were that 1) P. brochgrevinki, unlike many northern fishes, does not show thermal acclimation, and 2) environmental factors responsible for modification of peptide antifreeze synthesis in northern fishes do not elicit changes in AFGP synthesis in P. borchgrevinki.

• Research Organization: Department of Physiology and Biophysics, University of Illinois, Urbana
• OSTI ID: 7056397
• Journal Information: J. Exp. Zool.; (United States), Journal Name: J. Exp. Zool.; (United States) Vol. 220:2; ISSN JEZOA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ALANINES
AMINO ACIDS
ANIMALS
AQUATIC ORGANISMS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL ADAPTATION
BIOLOGICAL PATHWAYS
BIOSYNTHESIS
BODY
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
DIGESTIVE SYSTEM
FISHES
GLANDS
GLUCOPROTEINS
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
LEUCINE
LIVER
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PHYSIOLOGY
PROTEINS
REACTION KINETICS
SACCHARIDES
SYNTHESIS
TRITIUM COMPOUNDS
VERTEBRATES