Molecular modeling in the design of phospholipase A2 inhibitors

Ripka, William C.; Sipio, W. J.; Galbraith, W.

doi:10.1002/jcb.240400304

Cited by 14 publications

(6 citation statements)

References 15 publications

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“…Disruption of PLA, binding to a high-aftinity site is another potential therapeutic avenue (87,88). Molecular modeling, including modeling of single amino acid substitutions (89) and use of computer-driven programs, has also been applied to the study of PLA, inhibitors (90,91). The use of monoclonal antibodies against PLA,, as well as other potential immunotherapeutic strategies, is currently under investigation.…”

Section: Pharmacologic Regulationmentioning

confidence: 99%

Phospholipase A₂ and arthritis

Bomalaski¹,

Clark²

1993

Arthritis & Rheumatism

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Section: Pharmacologic Regulationmentioning

confidence: 99%

Phospholipase A₂ and arthritis

Bomalaski¹,

Clark²

1993

Arthritis & Rheumatism

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“…A more detailed evaluation of PLA, involvement in the acrosome reaction might be possible with the availability of more specific PLA, inhibitors. Effective PLA, inhibitors have recently been described (Davidson et al, 1986;Magolda and Galbraith, 1989;Ripka et al, 1989). However, their specificities of inhibition remain to be evaluated.…”

Section: Pla Inhibition Correlates Poorly With Effectsmentioning

confidence: 99%

Characterization and inhibitor sensitivity of human sperm phospholipase A₂: Evidence against pivotal involvement of phospholipase A₂ in the acrosome reaction

Anderson

Johnson

Bielfeld

et al. 1990

Molecular Reproduction Devel

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The kinetic properties and inhibitor sensitivity of human sperm phospholipase A2 (PLA2; EC 3.1.1.4) were studied. Phospholipase activity was isolated from human spermatozoa by acid extraction. Hydrolysis of dipalmitoyl phosphatidylcholine was specific to the sn-2 position. Activity was sensitive to product inhibition (60% inhibition by 0.1 mM lysophosphatidylcholine). The effects of Ca2+ and sodium deoxycholate on enzyme activity were biphasic; maximal activities were observed at 0.5 mM concentration of each agent. PLA2 was stimulated (135%) by 3% dimethylsulfoxide and was inhibited by elevated ionic strength (approximately 70% inhibition with either 0.2 M NaCl or 0.2 M KCl). Two molecular forms of PLA2 were kinetically distinguishable, one with an apparent Michaelis constant and maximal reaction velocity of 3.0 microM and 0.64 mlU/mg protein and the other with respective constants of 630 microM and 32.0 mlU/mg protein. Both forms of the enzyme were Ca2+ dependent and heat stable; however, the low-Km activity was less resistant to 60 degrees C preincubation at pH 7.5 (28% inactivation of low-Km activity after 45 min, as compared to no effect on high-Km activity). Quinacrine was a noncompetitive PLA2 inhibitor with Kis for low- and high-Km activities of 0.42 mM and 0.49 mM, respectively. Trifluoperazine (calmodulin antagonist) inhibited the high-Km activity noncompetitively (Ki = 87 microM) and the low-Km activity by a mechanism consistent with the removal of a nonessential activator. Dissociation and rate constants for inactivation of low- and high-Km activities by p-bromophenacyl bromide were 0.28 mM and 0.032 min-1, and 0.73 mM and 0.066 min-1, respectively. PLA2 was inhibited by p-nitrophenyl-p'-guanidinobenzoate, at higher concentrations (10(-4)-10(-3) M) than required to inhibit trypsinlike proteinases; p-aminobenzamidine, another potent trypsin/acrosin inhibitor, stimulated (approximately 40%) PLA2 at concentrations from 2-5 mM but inhibited PLA2 (40-50%) at a concentration of 10 mM. MnCl2 (5mM) inhibited low- and high-Km PLA2 activities by 77% and 76%, respectively. Quinacrine (0.4 mM), trifluoperazine (20 microM), p-bromophenacyl bromide (20 microM), and MnCl2 (5 mM) were tested as inhibitors of the ionophore A23187-induced human acrosome reaction. Inhibition was noted only with quinacrine (32%) and MnCl2 (93%). The effect of MnCl2 was restricted to an interaction with A23187, rather than with PLA2; p-Bromophenacyl bromide inhibited (P less than 0.05) PLA2 (29%) when added to intact spermatozoa but had no effect on the acrosome reaction. PLA2 inhibition was poorly correlated with the acrosome reaction.(ABSTRACT TRUNCATED AT 400 WORDS)

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“…A wide variety of PLA 2 inhibitors that act against the inflammatory effects of these enzymes have been reported in the literature [11][12][13][14]. Various compounds have been identified that act as competitive inhibitors of PLA 2 s [15,16], and include indoles [17], synthetic peptides [18], vitamin E [19], flavonoids [20] and a range of other substances derived from plant extracts [21].…”

Section: Introductionmentioning

confidence: 99%