Binding of quinacrine to acidic phospholipids and pancreatic phospholipase A2. Effects on the catalytic activity of the enzyme.
AuthorsMustonen P, Lehtonen JY, Kinnunen PK
JournalBiochemistry
PubMed ID9724516
'Binding of quinacrine to phospholipids and porcine pancreatic phospholipase A2 (PLA2) was investigated using fluorescence resonance energy transfer, Langmuir films, assay for the enzymatic activity, and molecular modeling. No significant binding of this drug to the zwitterionic phosphatidylcholine was observed whereas a high affinity for acidic phospholipids was revealed by ... More
Fluorometric assay for phospholipase A2 in serum.
AuthorsThuren T, Virtanen JA, Lalla M, Kinnunen PK
JournalClin Chem
PubMed ID3987000
In this fluorometric assay for phospholipase A2 (EC 3.1.1.4) in serum we use the fluorescent phospholipid analog 1-octacosanyl-2-(pyren-1-yl)hexanoyl-sn-glycero-3-phosphatid yl monomethyl ester as substrate. The optimized conditions are: 28 mumol of the substrate per liter of Tris buffer (20 mmol/L, pH 7.4). The hydrolytic reaction is allowed to proceed for 30 ... More
Substrate level modulation of the activity of phospholipase A2 in vitro by 12-O-tetradecanoylphorbol-13-acetate.
AuthorsMustonen P, Kinnunen PK
JournalBiochem Biophys Res Commun
PubMed ID1599455
The action of porcine pancreatic phospholipase A2 towards fluorescent phospholipid analogs is either enhanced or suppressed by 4 beta-12-O-tetradecanoylphorbol-13- acetate (TPA), depending on the chemical structure of the substrate and the concentration of Ca2+. In the presence of nmolar Ca2+ concentrations increasing [TPA] enhanced by approx. 5-fold the rate of ... More
Fluorescence-based assays of lipases, phospholipases, and other lipolytic enzymes.
AuthorsHendrickson HS
JournalAnal Biochem
PubMed ID8059934
In choosing an assay, one needs to consider the following questions: What level of sensitivity is required? Must the assay be continuous? Is the substrate readily available; can it be purchased or must it be custom synthesized? How specific is the substrate? How convenient is the method? How compatible is ... More
Activation of phospholipase A2 by adriamycin in vitro. Role of drug-lipid interactions.
AuthorsMustonen P, Kinnunen PK
JournalJ Biol Chem
PubMed ID2007582
To probe adriamycin-phospholipid interactions, the effects of this cytotoxin on the hydrolysis of a pyrene-labeled acidic alkyl-acyl phospholipid analog 1-octa-cosanyl-2-(6-pyren-1-yl)hexanoyl-sn-glycero-3-phos p hatidylmethanol (C28-O-PHPM) by porcine pancreatic phospholipase A2 (PLA2) were studied. In the absence of added Ca2+ adriamycin caused a 3-4-fold activation of hydrolysis of this pyrenelipid whereas an inhibition ... More
Effects of sphingosine on peripheral membrane interactions: comparison of adriamycin, cytochrome c, and phospholipase A2.
AuthorsMustonen P, Lehtonen J, Kõiv A, Kinnunen PK
JournalBiochemistry
PubMed ID8388718
As revealed by resonance energy transfer utilizing pyrene-labeled phosphatidylcholine donor, the mainly electrostatically controlled binding of adriamycin (Adr) and cytochrome c (cyt c) to mixed egg yolk phosphatidic acid/phosphatidylcholine (eggPA/eggPC, 15:85 molar ratio) liposomes was reversed upon the inclusion of increasing contents of sphingosine. At a [sphingosine]/[eggPA] molar ratio of ... More