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Biomedical subjects

Y Banno

Publications and source records attributed to Y Banno.

At least 55 records · Page 3Linked to original sources
PubMed1998

Evidence for the presence of multiple forms of Sph kinase in human platelets.

The intracellular distribution of sphingosine (Sph) kinase activity was examined in human platelets. A large proportion (72%) of the total activity was found to be associated with the membrane fraction, and the membrane-associated fraction had higher specific activity compared with the cytosolic enzyme. Most of the membrane-associated activity could be extracted with 1 M NaCl. The cytosolic activity was unstable upon heat treatment, with 80% of the activity being lost during incubation at 45 degreesC for 1 h, whereas the NaCl-extractable fraction was stable under the same conditions. When subjected to Mono Q column chromatography, the cytosolic fraction produced two activity peaks and the NaCl-extractable fraction gave a single peak. These three Sph kinase activities showed different responses to stimulation by beta-octylglucoside and inhibition by N, N-dimethylsphingosine and l-threo-dihydrosphingosine, suggesting the presence of multiple enzyme forms in human platelets.

Blood Platelets↗
PubMed1998

Ceramide formation leads to caspase-3 activation during hypoxic PC12 cell death. Inhibitory effects of Bcl-2 on ceramide formation and caspase-3 activation.

PC12 cells undergo apoptosis as well as necrosis following exposure to hypoxia. Following a 6-h hypoxic treatment, a time-dependent increase in intracellular ceramide level was observed with a concurrent decrease in sphingomyelin. It was also shown that the hypoxia-induced ceramide accumulation resulted from activation of neutral magnesium-dependent sphingomyelinase. Comparative kinetic analyses of the neutral sphingomyelinase in the cells under normoxia and hypoxia showed that hypoxia increased Vmax but did not affect Km of the enzyme. In PC12 cells overexpressing Bcl-2 which show strong resistance to hypoxia, sphingomyelin hydrolysis was decreased and activation of neutral sphingomyelinase was reduced. Addition of exogenous C2-ceramide induced cell death and activated caspase-3 as markedly as the hypoxia treatment. On the other hand, in PC12 cells overexpressing Bcl-2, significant decreases in cell death and inhibition of caspase-3 activation were observed after exogenous addition of C2-ceramide. The inhibitors of caspase-3 prevented cell death by either hypoxia or C2-ceramide. These results suggest that ceramide generated by activation of neutral magnesium-dependent sphingomyelinase mediates hypoxic cell death and that Bcl-2 has inhibitory effects on ceramide formation and caspase activation.

Animals↗
PubMed1998

Decreased phospholipase D (PLD) activity in ceramide-induced apoptosis of human keratinocyte cell line HaCaT.

Ceramide is recognized as an intracellular lipid second messenger, which induces various kinds of cell function including apoptosis. To evaluate the competence of ceramide on the keratinocyte apoptosis, we examined effects of a cell-permeable ceramide, N-acetylsphingosine (C2-ceramide), on a human keratinocyte cell line, HaCaT. C2-ceramide induced a distinct apoptosis in HaCaT cells in a time-dependent manner, as inferred by morphologic hallmarks of apoptosis such as bleb formation, cell body shrinkage, nuclear chromatin condensation, and internucleosomal DNA fragmentation. In sharp contrast, an inactive C2-ceramide, dihydroC2-ceramide, which lacks the 4-5trans double bond, failed to induce the apoptosis. The apoptotic HaCaT cells induced by C2-ceramide showed a significant suppression of phospholipase D (PLD) activity, regardless of the presence or absence of guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS). This indicates that C2-ceramide inhibits both GTPgammaS dependent and GTPgammaS independent PLD. The membrane associated GTPgammaS dependent PLD activity was stimulated by recombinant adenosine diphosphate-ribosylation factor. The adenosine diphosphate-ribosylation factor dependent and independent PLD activities were inhibited by C2-ceramide in a concentration dependent manner, but not by the inactive C2-ceramide. The concentration of C2-ceramide to inhibit the membrane associated PLD activity was comparable with that required for apoptosis induction in HaCaT cells. It was thus suggested that downregulation of PLD activity may be involved in the mechanism underlying C2-ceramide induced keratinocyte apoptosis.

Apoptosis↗
PubMed1998

Stimulation by G protein betagamma subunits of phospholipase C beta isoforms in human platelets.

Different phospholipase C (PLC) isoforms were located in human platelet cytosol and membranes. PLCgamma2 and PLCbeta3b were mainly located in the cytosol and PLCbeta2 and PLCbeta3a were in both cytosol and membranes by using specific antibodies against PLC isozymes (Banno Y, Nakashima S, Ohzawa M, Nozawa Y. J Biol Chem 1996; 271: 14989-94). Three PLC fractions activated by G protein betagamma subunits were purified from human platelet cytosol and membrane fractions. Two PLC fractions from membranes were identified as PLCbeta2 and PLCbeta3a, and one from cytosol was PLCbeta3b. These PLCbeta isoforms were activated by the purified betagamma subunits of brain G proteins in the order PLCbeta3b > PLCbeta3a > PLCbeta2. Western blot analysis of gamma subunits of the purified platelet G proteins with antibodies against various standard gamma subunits revealed that the major component of the gamma subunit of Gi2 and Gq was gamma5, and that gamma7 was a minor component. Studies using various subtypes of betagamma subunits, betagamma2, betagamma3, and betagamma7 purified from bovine brain, betagamma5 from bovine lung, or betagamma12 from bovine spleen, failed to show differences in their ability to stimulate the isolated platelet PLCbeta isoforms. These results suggest that the betagamma subunits of Gi2 and Gq have similar efficacy in regulation of effectors in human platelets.

Animals↗
PubMed1997

Inhibition of N-formylmethionyl-leucyl-phenylalanine-stimulated tyrosine phosphorylation and phospholipase D activation by quercetin in rabbit neutrophils.

We investigated the effect of bioflavonoid quercetin on tyrosine phosphorylation and phospholipase D (PLD, EC 3.1.4.4) activation in rabbit peritoneal neutrophils stimulated by N-formylmethionyl-leucyl-phenylalanine (fMLP). The quercetin dose-dependently inhibited degranulation and superoxide production in fMLP-stimulated neutrophils. A strong inhibitory effect of quercetin on the tyrosine phosphorylation of several proteins (40, 42, 43, 45, 46 and 75 kDa) was observed when the neutrophils were pretreated with different concentrations of quercetin. Furthermore, quercetin inhibited mitogen activated protein kinase (MAP kinase) and PLD activation induced by fMLP in a dose-dependent manner. The reduction in PLD activity was 30% at 0.1 microM and 70% at 100 microM of quercetin. These results suggest that impairment of neutrophil functions by quercetin may be due, at least in part, to inhibition of tyrosine phosphorylation and PLD activation.

Animals↗
PubMed1997

Nuclear ADP-ribosylation factor (ARF)- and oleate-dependent phospholipase D (PLD) in rat liver cells. Increases of ARF-dependent PLD activity in regenerating liver cells.

Two forms of phospholipase D (PLD) have been found to be present in nuclei isolated from rat hepatocytes by measuring phosphatidylbutanol produced from exogenous radiolabeled phosphatidylcholine in the presence of butanol. In nuclear lysates from either rat liver or ascites hepatoma AH 7974 cells, the PLD activity was markedly stimulated by a recombinant ADP-ribosylation factor (rARF) in the presence of the guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) and phosphatidylinositol 4, 5-bisphosphate. ATP and phorbol-12-myristate 13-acetate had no synergistic effect on this PLD activity. On the other hand, the nuclear PLD was stimulated by unsaturated fatty acids, especially by oleic acid. The ARF-dependent nuclear PLD activity was increased in the S-phase of the regenerating rat liver after partial hepatectomy and also was much higher in AH 7974 cells than in the resting rat liver. In contrast, the levels of the oleate-dependent PLD activity remained constant throughout the cell cycle in liver regeneration. The intranuclear levels of the stimulating proteins of the nuclear PLD activity, e.g. ARF, RhoA, and protein kinase Cdelta increased in the S-phase of the regenerating liver. These results suggested that the nuclear ARF-dependent PLD activity may be associated with cell proliferation.

ADP-Ribosylation Factors↗
PubMed1997

Increased activity of small GTP-binding protein-dependent phospholipase D during differentiation in human promyelocytic leukemic HL60 cells.

In response to dibutyryl cyclic AMP (dbcAMP) and all-trans retinoic acid, human promyelocytic leukemic HL60 cells differentiate into granulocyte-like cells. In cell lysate and in vitro reconstitution system, phospholipase D (PLD) activity in response to guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) was up-regulated by dbcAMP or all-trans retinoic acid treatment. In the present study, the mechanism(s) for increased PLD activity during differentiation was examined. Western blot analysis revealed that the contents of ADP-ribosylation factor, Rac2, and Cdc42Hs but not RhoA and Rac1 in the cytosolic fraction were elevated during differentiation. However, the cytosolic fraction from undifferentiated cells was almost equally potent as the cytosolic fraction from differentiated cells in the ability to stimulate membrane PLD activity. It was shown that the GTPgammaS-dependent PLD activity in membranes from differentiated cells was much higher than that in membranes from undifferentiated cells, suggesting that the increased PLD activity during differentiation was due to alterations in some membrane component(s). Clostridium botulinum ADP-ribosyltransferase C3 and C. difficile toxin B, which are known as inhibitors of RhoA and Rho family proteins, respectively, effectively suppressed PLD activity in membranes from differentiated cells. In fact, the amount of membrane-associated RhoA was increased during differentiation. Furthermore, the extent of GTPgammaS-dependent PLD activity partially purified from membranes from differentiated cells was greater than that from membranes from undifferentiated cells in the presence of recombinant ADP-ribosylation factor 1. The PLD (hPLD1) mRNA level was observed to be up-regulated during differentiation, as inferred by reverse transcription-polymerase chain reaction. Our results suggest the possibility that the increased Rho proteins in membranes and the changed level of PLD itself may be, at least in part, responsible for the increase in GTPgammaS-dependent PLD activity during granulocytic differentiation of HL60 cells.

ADP-Ribosylation Factors↗
PubMed1997

Involvement of Rho family proteins in prostaglandin F2 alpha-induced phospholipase D activation in the osteoblast-like cell line MC3T3-E1.

To examine the role of Rho family proteins in prostaglandin F2 alpha (PGF2 alpha)-mediated phospholipase D (PLD) activation of osteoblast-like cell line MC3T3-E1 cells, we used Toxin-B from Clostridium difficile, which inhibits Rho family proteins by monoglucosylation. Pretreatment of [3H]myristic acid-labeled MC3T3-E1 cells with Toxin B induced rounding-up of the cells and inhibited the PGF2 alpha-induced PLD activation by 60%, but not the phospholipase C (PLC) activation. Cytochalasin D also induced rounding the cells, but showed a small inhibition in the PLD activation. Brefeldin A (BFA) had marginal inhibitory effect on the PGF2 alpha-induced PLD activation. In digitonin-permeabilized MC3T3-E1 cells, [3H]P But formation was stimulated by guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) or 4 beta-phorbol 12-myristate 13-acetate (PMA) in the presence of Ca2+ (1 microM) and ATP (1 mM), and phosphatidylinositol 4,5-bisphosphate (PIP2) was also required for its full PLD activation. Pretreatment of the digitonin-permeabilized MC3T3-E1 cells with Toxin B reduced the GTP gamma S- and PMA-stimulated PLD activities by 80% and 60%, respectively. On the other hand, C3 toxin which inhibits Rho by ADP-ribosylation, exerted a partial inhibitory effect on the GTP gamma S-stimulated PLD activity. These results suggest that Cdc42 as well as RhoA appear to be involved in the PLD activation mediated by PGF2 alpha and also that the PLD activation may be independent of actin cytoskeleton in MC3T3-E1 cells.

ADP Ribose Transferases↗
PubMed1997

Changes in the activity and mRNA levels of phospholipase D during ceramide-induced apoptosis in rat C6 glial cells.

N-Acetylsphingosine (C2-ceramide), a membrane-permeable analogue, induced apoptosis in C6 glial cells. Phase-contrast micrographs showed that the round cells appeared 3 h after exposure to 25 microM C2-ceramide and the number of floating cells increased time-dependently. Staining with Hoechst 33258 dye showed condensed or fragmented nuclei in round cells at 12 h. DNA fragmentation was also observed by agarose gel electrophoresis at 12 h. To understand the mechanism underlying glial cell death induced by C2-ceramide treatment, changes in phospholipase D (PLD) activity in response to guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS) and expression of mRNA levels of PLD isozymes were examined. In cell lysate, GTPgammaS-dependent PLD activity was down-regulated after ceramide treatment in a time-dependent manner. In the in vitro PLD assay, membrane-associated PLD activation in response to recombinant ADP-ribosylation factor 1 was greatly suppressed. Furthermore, levels of rPLD1a and rPLD1b mRNAs were found to be down-regulated, whereas the level of rPLD2 mRNA increased gradually, peaking at 3 h, followed by a slow decrease, as inferred by reverse transcription-polymerase chain reaction. Decreases in GTPgammaS-dependent PLD activity were well correlated with those in rPLD1a and rPLD1b mRNAs levels. Taken together, these data suggest that levels of PLD enzymes might be decreased by ceramide treatment.

ADP-Ribosylation Factors↗
PubMed1997

Purification of a factor from CSF in patient after SAH which induces the cytosolic free calcium elevation in vascular smooth muscle cells.

Cerebrospinal fluid from patients with aneurysmal subarachnoid hemorrhage induces the elevation of cytosolic free calcium [Ca2+]i in cultured vascular smooth muscle cells. We have purified a [Ca2+]i elevating factor from cerebrospinal fluid of a patient with subarachnoid hemorrhage due to aneurysm rupture. The calcium-elevating protein factor was purified to homogeneity by ammonium sulfate precipitation and a combination of Mono Q, Superose 12, and Mono S columns using liquid chromatography. Fifteen microgram of the purified protein was obtained from 340 mg of cerebrospinal fluid proteins and the molecular mass of the protein was estimated to be 81 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis. It was also shown that the purified protein was cross-reactive with anti-human transferrin antibody. These results suggested that transferrin may be involved with the cerebral vasospasm after subarachnoid hemorrhage.

Animals↗
PubMed1996

Effect of Clostridium difficile toxin B on IgE receptor-mediated signal transduction in rat basophilic leukemia cells: inhibition of phospholipase D activation.

Antigen (Ag)-stimulated phospholipase D (PLD) activation and secretion were almost abolished by pretreatment of rat basophilic leukemia (RBL)-2H3 cells for 4 h with 5 ng/ml Clostridium difficile Toxin B which is known to inhibit Rho family proteins (Rho, Cdc42, Rac). The concentration-dependent inhibition of PLD activation was well correlated with the level of glucosylation of Rho family proteins. In streptolysin O-permeabilized RBL cells, Toxin B suppressed [3H] phosphatidylbutanol (PBut) formation in response to guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) and phorbol 12-myristate 13-acetate (PMA) by 67 and 43%, respectively. The synergistic PLD activation by GTP gamma S and PMA was also reduced by Toxin B by 67%. These results suggest that the IgE receptor-coupled PLD activation is largely mediated by Rho proteins.

Animals↗
PubMed1996

Differential translocation of phospholipase C isozymes to integrin-mediated cytoskeletal complexes in thrombin-stimulated human platelets.

To investigate a role of phospholipase C (PLC) isozymes in the integrin alphaIIbbeta3-mediated signaling, their location was examined in thrombin-activated human platelets, revealing different regulation of their translocation to the cytoskeleton (CSK). In resting platelets, the major PLCs such as PLCbeta2, PLCbeta3a (155 kDa), and PLCgamma2 and the minor PLCs (PLCbeta1 and PLCgamma1) were located in the Triton X-100-soluble (Tx.Sol) fraction and the membrane skeleton, whereas PLCbeta3b (140 kDa) was present only in Tx.Sol fraction when examined by Western immunoblotting. Thrombin stimulation caused a rapid and transient translocation of PLCbeta3a and PLCbeta3b and a slower accumulation of PLCbeta2 and PLCgamma2 in the reorganized CSK. The translocation to CSK of both PLCbeta3a and PLCbeta3b, but not PLCbeta2, was dependent on integrin alphaIIbbeta3-mediated aggregation. Furthermore, an actin polymerization inhibitor, cytochalasin D, or a protein tyrosine kinase inhibitor, genistein, abolished the CSK association of alphaIIbbeta3, PLCbeta3a, and PLCbeta3b. In the genistein-pretreated platelets, pp60(c-)src, Gq, and protein kinase Calpha were no longer able to associate with CSK. In contrast, these agents had no or marginal inhibitory effects on the CSK association of PLCbeta2 and Gi2. The late diacylglycerol generation induced by thrombin stimulation was significantly reduced by the genistein treatment. These results suggest that the integrin alphaIIbbeta3-mediated cytoskeletal association of PLCbeta3 is regulated by protein tyrosine kinase and also that the activation of the relocated PLC may play a role in the late platelet-to-platelet aggregation in thrombin-stimulated human platelets.

Actins↗
PubMed1996

Regulation of membrane-bound phospholipase D by protein kinase C in HL60 cells. Synergistic action of small GTP-binding protein RhoA.

In HL60 cells, the membrane-bound phospholipase D (PLD) was stimulated by 4beta-phorbol 12-myristate 13-acetate (PMA) in the presence of the cytosolic fraction from HL60 cells or rat brain. The cytosolic factor for this PMA-induced PLD activation was subjected to purification from rat brain by sequential chromatographies. The PLD stimulating activity was found in protein kinase C (PKC) fraction containing alpha, betaI, betaII, and gamma isozymes. PKC isozymes were further separated by hydroxylapatite chromatography. PKCalpha and - beta, but not gamma, isozymes were found to activate membrane-bound PLD. PKCalpha was much more effective than PKCbeta for PLD activation. Millimolar concentrations of MgATP were required for the PKC-mediated PLD activation in HL60 membranes. MgATP is utilized to maintain the levels of phosphatidylinositol 4,5-bisphosphate (PIP2) under these assay conditions. The PKC-mediated PLD activation was completely inhibited by neomycin, a high affinity ligand for PIP2, and this suppression was recovered by the addition of exogenous PIP2. Thus, these results suggest that PIP2 is supposed to play a key role in PKC-mediated PLD activity in HL60 membranes. Furthermore, PKCalpha-mediated PLD activation was potentiated by the addition of recombinant RhoA protein in the presence of guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS). The results obtained here indicate that PKCalpha and RhoA (GTP form) exert a synergistic action in the membrane-bound PLD activation in HL60 cells.

Animals↗
PubMed1996

Ceramide inhibits IgE-mediated activation of phospholipase D, but not of phospholipase C, in rat basophilic leukemia (RBL-2H3) cells.

Ceramide, a product of sphingomyelin hydrolysis by sphingomyelinase, elicits various cellular functions and has recently been regarded as a second messenger. To investigate the role of ceramide in rat basophilic leukemia (RBL-2H3) cells, the effects of a cell-permeable analogue, N-acetylsphingosine (C2-ceramide), on Ag-mediated cellular responses were examined. C2-Ceramide inhibited Ag- or PMA-induced activation of phospholipase D (PLD), whereas Ca2+ ionophore A23187-induced PLD activation was not affected. C2-Ceramide failed to inhibit PLD activity in two different in vitro assay systems. Since PLD activity is known to be regulated by several factors, the effects of C2-ceramide on these factors were examined. We have previously reported the possible involvement of protein tyrosine kinase in Ag-mediated PLD activation. However, C2-ceramide had no effect on Ag-induced protein tyrosine phosphorylation, including mitogen-activated protein (MAP) kinases. In fura-2-loaded RBL-2H3 cells, C2-ceramide suppressed Ag-induced Ca2+ influx, leaving initial Ca2+ increase and inositol phosphate production unaffected. Western blot analysis revealed that Ag caused translocation of protein kinase C (PKC) alpha, beta 1, beta 2, delta and epsilon isozymes from cytosol to membrane fraction. Translocation of alpha, beta 1, and beta 2 isozymes was specifically prevented by C2-ceramide. Moreover, C2-ceramide suppressed Ag-induced serotonin release. In the absence of extracellular Ca2+, Ag-induced PLD activation and release reaction were greatly reduced. The inhibitory profile was nearly the same as that obtained in C2-ceramide-treated cells. These results suggest that C2-ceramide inhibits Ag-induced PLD activation and serotonin release, probably through the blockage of Ca2+ influx and translocation of Ca(2+)-dependent PKC isozymes in RBL-2H3 cells.

Animals↗
PubMed1996

Membrane-associated phospholipase D activity in neural cell line PC12.

Stimulation of PC12 cells with carbachol (Cch) or phorbol 12-myristate 13-acetate (PMA) induced [3H]phosphatidylbutanol (PBut) production. Depletion of extracellular Ca2+ abolished the Cch-mediated phospholipase D (PLD) activation, indicating the requirement of Ca2+ influx. Two different types of PLD activity, oleate-dependent and GTP gamma S-dependent, were examined by using exogenous [3H]phosphatidylcholine substrate. PLD activity of the membrane fraction of PC12 cells was highly dependent on oleate and independent of GTP gamma S. This profile is in sharp contrast to that observed in HL60 cells showing the profound GTP gamma S-induced activation of PLD. The oleate-dependent PLD activity of PC12 membrane was inhibited by high concentrations of Ca2+ and Mg2+. These results indicate that Ca2+ may not directly activate PLD but through some Ca(2+)-dependent mechanism(s) in Cch-stimulated cells.

Animals↗
PubMed1996

Effects of Clostridium difficile toxin A and toxin B on phospholipase D activation in human promyelocytic leukemic HL60 cells.

The possible involvement of Rho family GTP-binding proteins in the regulation of phospholipase D (PLD) activity has recently been demonstrated. In the present study, to further examine the role of Rho family proteins in PLD activation of human promyelocytic leukemic HL60 cells, we used toxin A and toxin B from the anaerobic bacterium Clostridium difficile, which was shown to glucosylate Rho family proteins and inhibit their interaction with effectors. Pretreatment of [3H]oleic acid-labeled HL60 cell lysates with either one of the toxins resulted in a remarkable inhibition of membrane PLD activity stimulated by guanosine 5'-O-(3-thiotriphosphate) (GTPgammaS). The magnitude of inhibition of PLD activity was correlated well with the extent of toxin A- or B-induced glucosylation of 22-kDa RhoA in HL60 cells, toxin B being more effective than toxin A. GTPgammaS-stimulated PLD activation measured with the exogenous substrate containing phosphatidylinositol 4,5-bisphosphate was also inhibited by toxin B. Toxin B had no effect on GTP-gammaS-induced translocation of RhoA from cytosol to membranes. Furthermore, the toxin B pretreatment also suppressed PLD activation induced by 4beta-phorbol 12-myristate 13-acetate in HL60 cell lysates. Thus, it was indicated that Rho family proteins play a key role in GTPgammaS- and 40-phorbol 12-myristate 13-acetate-induced PLD activity in HL60 cells. In addition, the results obtained here indicate that C. difficile toxins are a useful tool for researching the regulation of the Rho family protein-mediated PLD activation and also provide a clue toward understanding the pathogenic background of pseudomembranous colitis from the viewpoint of signal transduction.

ADP-Ribosylation Factors↗
PubMed1995

Purification and characterization of lysophospholipase-transacylase (h-LPTA) from a highly virulent strain of Candida albicans.

A lysophospholipase-transacylase (h-LPTA) was purified to homogeneity from a clinical isolate of Candida albicans (C. albicans) that had high extracellular phospholipase activity (strain 16240). The purified enzyme was a glycoprotein with molecular mass of 84 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The specific activities of the enzyme were 117 mumol/min per mg protein for fatty acid release and 459 mumol/min per mg protein for phosphatidylcholine (PC) formation. An apparent Km of the hydrolase activity of the enzyme for 1-palmitoyl-sn-glycero-3-phosphocholine (1-palmitoyl-lyso-PC) was 60.6 microM. The enzyme had a pH optimum at 6.0. Transacylase activity of the enzyme was partially inhibited by palmitoylcarnitine (35% inhibition) and N-ethylmaleimide. In contrast, the hydrolase activity of the enzyme was stimulated by palmitoylcarnitine but was partially inhibited by N-ethylmaleimide. The enzyme exhibited broad specificity to lyso-phospholipids. The h-LPTA activity was not dependent on divalent cations (Ca2+ and Mg2+) and was not inhibited by addition of EDTA or EGTA. These results show that C. albicans strain 16240 with high extracellular phospholipase activity produced h-LPTA in large amount. This enzyme is biochemically distinct from the LPTA enzyme previously isolated from C. albicans 3125.

Acyltransferases↗