Deglycosylation of dopamine. beta. -hydroxylase
Dopamine ..beta..-hydroxylase (DBH) is a glycoprotein with approximately 5% carbohydrate by weight in its soluble form. The adrenal medullary enzyme contains biantennary complex oligosaccharides and high-mannose oligosaccharides in a molar ratio of approximately 2:1. In their work they enzymatically removed the oligosaccharide chains from DBH, quantitated the amount removed, and studied the effects of sugar removal on the activity of the enzyme. Various glycosidic enzymes were used for carbohydrate removal and the time course was followed by polyacrylamide gel electrophoresis. Evidence for sugar removal was shown by a modification of the Western blot technique utilizing /sup 125/I-Concanavalin A. Steady state kinetic data of deglycosylated DBH infer no major differences between the native and the deglycosylated protein with regards to the substrates tyramine and oxygen. The K/sub m/ for tyramine was 2.17 mM and 1.66 mM for the native and the deglycosylated protein respectively. The V/sub max/ values (pH 5.5) for the two forms of the enzyme were almost similar with the deglycosylated DBH being 15% lower. These data indicate that the oligosaccharide moieties present on DBH do not play a role in catalysis.
- Research Organization:
- Pennsylvania State Univ., University Park
- OSTI ID:
- 6074133
- Report Number(s):
- CONF-870644-
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 46:6; ISSN FEPRA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
AGGLUTININS
AMINES
ANTIBODIES
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
CARBOHYDRATES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CATALYSIS
CONCANAVALIN
DAYS LIVING RADIOISOTOPES
DOPAMINE
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ELECTROPHORESIS
ENZYME ACTIVITY
ENZYMES
GLUCOPROTEINS
HEMAGGLUTININS
HYDROXY COMPOUNDS
HYDROXYLASES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
LECTINS
MOLECULAR STRUCTURE
NEUROREGULATORS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PHENOLS
POLYPHENOLS
PROTEINS
RADIOISOTOPES
REMOVAL
SACCHARIDES
SYMPATHOMIMETICS