Identification of a membrane-bound, glycol-stimulated phospholipase A sub 2 located in the secretory granules of the adrenal medulla

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00216a023· OSTI ID:5614601

Hildebrandt, E; Albanesi, J P ^[1]

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1. Univ. of Texas Southwestern Medical Research Center, Dallas (USA)

Chromaffin granule membranes prepared from bovine adrenal medullae showed Ca{sup 2+}-stimulated phospholipase A{sub 2} (PLA{sub 2}) activity when assayed at pH 9.0 with phosphatidylcholine containing an ({sup 14}C)-arachidonyl group in the 2-position. However, the activity occurred in both soluble and particulate subcellular fractions, and did not codistribute with markers for the secretory granule. PLA{sub 2} activity in the granule membrane preparation was stimulated dramatically by addition of glycerol, ethylene glycole, or poly(ethylene glycol). This glycol-stimulated PLA{sub 2} activity codistributed with membrane-bound dopamine {beta}-hydroxylase, a marker for the granule membranes, through the sequence of differential centrifugation steps employed to prepare the granule membrane fraction, as well as on a sucrose density gradient which resolved the granules from mitochondria, lysosomes, and plasma membrane. The glycol-stimulated PLA{sub 2} of the chromaffin granule was membrane-bound, exhibited a pH optimum of 7.8, retained activity in the presence of EDTA, and was inactivated by p-bromophenacyl bromide. When different {sup 14}C-labeled phospholipids were incorporated into diarachidonylphosphatidylcholine liposomes, 1-palmitoyl-2-arachidonylphosphatidylcholine was a better substrate for this enzyme than 1-palmitoyl-2-oleylphosphatidylcholine or 1-acyl-2-arachidonyl-phosphatidylethhanolamine, and distearoylphosphatidylcholine was not hydrolyzed.

• OSTI ID: 5614601
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 30:2; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL GLANDS
ALCOHOLS
AMINES
AMMONIUM COMPOUNDS
ANIMALS
ARACHIDONIC ACID
BIOCHEMISTRY
BODY
CARBOXYLESTERASES
CARBOXYLIC ACIDS
CATTLE
CELL CONSTITUENTS
CELL MEMBRANES
CHEMISTRY
CHOLINE
COMPARTMENTS
DOMESTIC ANIMALS
DRUGS
ENDOCRINE GLANDS
ENZYME ACTIVITY
ENZYMES
ESTERASES
ESTERS
GLANDS
GLYCOLS
HORMONES
HYDROLASES
HYDROXY COMPOUNDS
LIPASES
LIPIDS
LIPOTROPIC FACTORS
MAMMALS
MEMBRANES
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANS
PHOSPHOLIPIDS
PURIFICATION
QUATERNARY COMPOUNDS
RUMINANTS
SECRETION
VERTEBRATES