Glycosyl-phosphatidylinositol anchored acetylcholinesterase as substrate for phosphatidylinositol-specific phospholipase C from Bacillus cereus

Synthesis, Structure−Activity Relationships, and the Effect of Polyethylene Glycol on Inhibitors of Phosphatidylinositol-Specific Phospholipase C fromBacillus cereus

“…The inhibition by glucosaminyl(α1→6)- d - myo -inositol (GlcN(α1→6)Ins, 28 ) is 5 times greater than by myo -inositol, arguing the presence of this portion of the GPI anchor improves binding to the enzyme. These results are in agreement with the observation that PI-PLC has a higher affinity for GPI substrates than for PI, demonstrated by apparent K M values for GPI substrates that are at least 2 orders of magnitude lower than the K M for PI …”

Synthesis, Structure−Activity Relationships, and the Effect of Polyethylene Glycol on Inhibitors of Phosphatidylinositol-Specific Phospholipase C fromBacillus cereus

“…The inhibition by glucosaminyl(α1→6)- d - myo -inositol (GlcN(α1→6)Ins, 28 ) is 5 times greater than by myo -inositol, arguing the presence of this portion of the GPI anchor improves binding to the enzyme. These results are in agreement with the observation that PI-PLC has a higher affinity for GPI substrates than for PI, demonstrated by apparent K M values for GPI substrates that are at least 2 orders of magnitude lower than the K M for PI …”

Crystal Structure of Phosphatidylinositol-Specific Phospholipase C from Bacillus cereus in Complex with Glucosaminyl(α1→6)-d-myo-inositol, an Essential Fragment of GPI Anchors,

“…However, two compensating effects are observed; the enzyme binds GPI-anchored proteins with a higher affinity than PI, but the turnover for GPI cleavage is slower. As a net result, the ratio V max /K M is approximately the same for the two substrates (Stieger & Brodbeck, 1991). These data can be interpreted to indicate that recognizes PI-PLC not only the PI moiety of the anchor but also some of the remaining components.…”

“…In this case, the most likely place on the surface of PI-PLC for glycan recognition is the shallow channel extending from the active site pocket that contains a number of polar amino acids capable of forming hydrogen bonds with sugar molecules. Stieger and Brodbeck (1991) also report slight differences in K M for PI-PLC with respect to different anchors, which seem to be due to the glycan composition of the respective anchor. However, highly specific interactions with the glycans seem unlikely as they often carry a wide variety of additional modifications, especially at the mannose ring adjacent to the glucosamine ring (Englund, 1993).…”

Phosphatidylinositol Hydrolysis by Glycosylphosphatidylinositol Phospholipase C

“…5. PI-PLC (Stieger and Brodbeck, 1991), peanut GPI-hydrolyzing phospholipase C (Bü tikofer and Brodbeck, 1993), and T. brucei GPI-PLC (this work) for GPI are considerably lower than for PI, indicating that the enzymes specifically recognize glycan components of the GPI structure. Although such comparisons between kinetic parameters of PI versus GPI hydrolysis must be interpreted with caution, these findings are consistent with the observation that certain compounds including GPI glycan derivatives affect both T. brucei GPI-PLC and B. cereus PI-PLC activities, although details of the inhibitory effects on the two enzymes are quite distinct (Morris et al, 1995).…”

Synthesis, Structure−Activity Relationships, and the Effect of Polyethylene Glycol on Inhibitors of Phosphatidylinositol-Specific Phospholipase C fromBacillus cereus

“…The inhibition by glucosaminyl(α1→6)- d - myo -inositol (GlcN(α1→6)Ins, 28 ) is 5 times greater than by myo -inositol, arguing the presence of this portion of the GPI anchor improves binding to the enzyme. These results are in agreement with the observation that PI-PLC has a higher affinity for GPI substrates than for PI, demonstrated by apparent K M values for GPI substrates that are at least 2 orders of magnitude lower than the K M for PI …”

Crystal Structure of Phosphatidylinositol-Specific Phospholipase C from Bacillus cereus in Complex with Glucosaminyl(α1→6)-d-myo-inositol, an Essential Fragment of GPI Anchors,

“…However, two compensating effects are observed; the enzyme binds GPI-anchored proteins with a higher affinity than PI, but the turnover for GPI cleavage is slower. As a net result, the ratio V max /K M is approximately the same for the two substrates (Stieger & Brodbeck, 1991). These data can be interpreted to indicate that recognizes PI-PLC not only the PI moiety of the anchor but also some of the remaining components.…”

“…In this case, the most likely place on the surface of PI-PLC for glycan recognition is the shallow channel extending from the active site pocket that contains a number of polar amino acids capable of forming hydrogen bonds with sugar molecules. Stieger and Brodbeck (1991) also report slight differences in K M for PI-PLC with respect to different anchors, which seem to be due to the glycan composition of the respective anchor. However, highly specific interactions with the glycans seem unlikely as they often carry a wide variety of additional modifications, especially at the mannose ring adjacent to the glucosamine ring (Englund, 1993).…”

Phosphatidylinositol Hydrolysis by Glycosylphosphatidylinositol Phospholipase C

“…5. PI-PLC (Stieger and Brodbeck, 1991), peanut GPI-hydrolyzing phospholipase C (Bü tikofer and Brodbeck, 1993), and T. brucei GPI-PLC (this work) for GPI are considerably lower than for PI, indicating that the enzymes specifically recognize glycan components of the GPI structure. Although such comparisons between kinetic parameters of PI versus GPI hydrolysis must be interpreted with caution, these findings are consistent with the observation that certain compounds including GPI glycan derivatives affect both T. brucei GPI-PLC and B. cereus PI-PLC activities, although details of the inhibitory effects on the two enzymes are quite distinct (Morris et al, 1995).…”

Synthesis, Structure−Activity Relationships, and the Effect of Polyethylene Glycol on Inhibitors of Phosphatidylinositol-Specific Phospholipase C fromBacillus cereus

“…The inhibition by glucosaminyl(α1→6)- d - myo -inositol (GlcN(α1→6)Ins, 28 ) is 5 times greater than by myo -inositol, arguing the presence of this portion of the GPI anchor improves binding to the enzyme. These results are in agreement with the observation that PI-PLC has a higher affinity for GPI substrates than for PI, demonstrated by apparent K M values for GPI substrates that are at least 2 orders of magnitude lower than the K M for PI …”

Crystal Structure of Phosphatidylinositol-Specific Phospholipase C from Bacillus cereus in Complex with Glucosaminyl(α1→6)-d-myo-inositol, an Essential Fragment of GPI Anchors,

“…However, two compensating effects are observed; the enzyme binds GPI-anchored proteins with a higher affinity than PI, but the turnover for GPI cleavage is slower. As a net result, the ratio V max /K M is approximately the same for the two substrates (Stieger & Brodbeck, 1991). These data can be interpreted to indicate that recognizes PI-PLC not only the PI moiety of the anchor but also some of the remaining components.…”

“…In this case, the most likely place on the surface of PI-PLC for glycan recognition is the shallow channel extending from the active site pocket that contains a number of polar amino acids capable of forming hydrogen bonds with sugar molecules. Stieger and Brodbeck (1991) also report slight differences in K M for PI-PLC with respect to different anchors, which seem to be due to the glycan composition of the respective anchor. However, highly specific interactions with the glycans seem unlikely as they often carry a wide variety of additional modifications, especially at the mannose ring adjacent to the glucosamine ring (Englund, 1993).…”

Phosphatidylinositol Hydrolysis by Glycosylphosphatidylinositol Phospholipase C

“…5. PI-PLC (Stieger and Brodbeck, 1991), peanut GPI-hydrolyzing phospholipase C (Bü tikofer and Brodbeck, 1993), and T. brucei GPI-PLC (this work) for GPI are considerably lower than for PI, indicating that the enzymes specifically recognize glycan components of the GPI structure. Although such comparisons between kinetic parameters of PI versus GPI hydrolysis must be interpreted with caution, these findings are consistent with the observation that certain compounds including GPI glycan derivatives affect both T. brucei GPI-PLC and B. cereus PI-PLC activities, although details of the inhibitory effects on the two enzymes are quite distinct (Morris et al, 1995).…”