Pancreatic porcine phospholipase A2 catalyzed hydrolysis of phosphatidylcholine in lecithin-bile salt mixed micelles: Kinetic studies in a lecithin-sodium cholate system

Hoffman, William J.; Vahey, Marianne; Hajdu, Joseph

doi:10.1016/0003-9861(83)90155-8

Cited by 26 publications

(21 citation statements)

References 30 publications

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“…A PC forma micelas juntamente com sais biliares, ácidos graxos livres, mono e diacil-gliceróis, esteróides e outros nutrientes no duodeno. A mistura de PC, sais biliares e lipossolúveis do alimento são alvo da atividade da fosfolipase A2 secretada pelo pâncreas, formando Lisofosfatidilcolina (ou, por abreviação, LPC) na micela (Nalbone et al, 1980;Hoffman et al, 1983).…”

Section: Suplementação Com Enzimas Endógenasunclassified

Interações químico-fisiolóficas entre acidificantes, probióticos, enzimas e lisofosfolipídios na digestão de leitões

Júnior

da²

2009

R. Bras. Zootec.

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RESUMO -Uma digestão e absorção de nutrientes eficientes, associadas a um bom estado de saúde animal, são necessidades fundamentais na competitiva indústria de produção de proteína animal. Uma má absorção de nutrientes, além de causar perdas econômicas, é fonte de desequilíbrio na microflora microbiana intestinal, abrindo portas para diarréias e outras enfermidades intestinais, ou mesmo facilitando problemas sistêmicos de saúde animal. Estes problemas produtivos tornam-se ainda mais críticos no cenário atual de aumento de risco com a progressiva restrição ao uso de antibióticos promotores de crescimento no mundo. Animais jovens, como os leitões, são mais suscetíveis a estes problemas devido ao seu estado de desenvolvimento incompleto, com menor quantidade de enzimas e capacidade digestiva, associado a um sistema imune imaturo e menos eficiente. O intestino destes animais se encontra em fase de colonização, mais suscetível a desequilíbrios de microflora e problemas entéricos. Diversas novas tecnologias vêm sendo desenvolvidas e implementadas para enfrentar estes desafios, como, por exemplo, as enzimas, os ácidos orgânicos, os lisofosfolipídios e os probióticos. Será discutido como a suplementação de dietas com estas tecnologias possui potencial para permitir a formulação de rações de menor densidade nutricional, gerando menor poluição ambiental, e como elas promovem melhor desempenho zootécnico e saúde animal. Também serão abordadas evidências que apontam para a atuação conjunta e potencialmente sinérgica destas tecnologias no trato gastrointestinal para aumentar a digestibilidade dos nutrientes e afetar de forma positiva o equilíbrio da microflora residente no intestino. Palavras-chave: ácidos orgânicos, antibióticos, enzimas, lisofosfolipídios, probióticosChemical and philosophic interactions of acidifiers, probiotics, enzymes and lysophospholipids in the piglest digestion ABSTRACT -An efficient digestion and nutrients absorption, coupled with good animal health status, are fundamental needs in the competitive animal protein industry. Poor absorption of nutrients cause economic losses, and are a source of imbalance in the microbial intestinal microflora, opening doors to diarrhea and other intestinal diseases, or even facilitating systemic problems of animal health. These problems become even more critical in the current scenario of increased risk with the progressive restriction of the use of antibiotic growth promoters around the world. Young animals, as piglets, are more susceptible to these problems due to the incomplete state of development of these animals, with less capacity and digestive enzymes, associated with an immature and less efficient immune system. The intestine of these animals is still in colonization process, so there is higher susceptibility to microflora imbalance and enteric problems. Several new technologies have been developed and implemented to address these challenges, such as Enzymes, Organic Acids, Probiotics and Lysophospholipids. A discussion will be presented showing how the supp...

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Section: Suplementação Com Enzimas Endógenasunclassified

Interações químico-fisiolóficas entre acidificantes, probióticos, enzimas e lisofosfolipídios na digestão de leitões

Júnior

da²

2009

R. Bras. Zootec.

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“…With this new form it is shown that the kinetic parameters of the model can be individually determined, which was not possible before without making assumptions concerning the headgroup surface areas [3]. In earlier work the kinetic parameters were determined in a combined form [4]. The significance of determining the kinetic parameter, namely the catalytic rate, denoted by k 3 in this work, is that the effect of the biophysical property of the aggregate on k 3 can be investigated and this can lead to mechanistic models for enzyme activation.…”

Section: Introductionmentioning

confidence: 99%

“…The model used to analyze the kinetic data treats the interface as a cofactor and was originally applied towards the study of kinetics of phospholipase A 2 activity on Triton X-100/ phospholipid micelles [3] and later, on sodium cholate/lipid micelles [4]. We begin with a recasting of the equation for the initial rate of hydrolysis to reveal a straightforward dependence on the surface concentration of lipids in a form that is more accessible for analysis of experimental data.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of the kinetics of phospholipase C activity toward mixed micelles of sodium deoxycholate and dimyristoylphosphatidylcholine

Ranganathan

Tcacenco

Rosseto

et al. 2006

Biophysical Chemistry

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“…The mechanism of the rate enhancement remains to be established. The confusion arises due to a dependence of the rate of hydrolysis of the phosphatidylcholine dispersions with monodisperse bile salts that is biphasic 5,6,8,9 . The rising phase is consistent with the enhanced PLA2 binding and k cat *-activation by the anionic charge induced by the bile salt anions partitioned onto the surface of a zwitterionic bilayer 10-13 .…”

Section: Introductionmentioning

confidence: 99%

Structural Basis for Bile Salt Inhibition of Pancreatic Phospholipase A2

Pan¹,

Bahnson²

2007

Journal of Molecular Biology

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SummaryBile salt interactions with phospholipid monolayers of fat emulsions are known to regulate the actions of gastrointestinal lipolytic enzymes in order to control the uptake of dietary fat. Specifically, on the lipid/aqueous interface of fat emulsions, the anionic portions of amphipathic bile salts have been thought to interact with and activate the enzyme group-IB phospholipase A2 (PLA2) derived from the pancreas. To explore this regulatory process, we have determined the crystal structures of the complexes of pancreatic PLA2 with the naturally occurring bile salts: cholate, glycocholate, taurocholate, glycochenodeoxycholate, and taurochenodeoxycholate. The five PLA2-bile salt complexes each result in a partly occluded active site, and the resulting ligand binding displays specific hydrogen bonding interactions and extensive hydrophobic packing. The amphipathic bile salts are bound to PLA2 with their polar hydroxyl and sulfate/carboxy groups oriented away from the enzyme's hydrophobic core. The impaired catalytic and interface binding functions implied by these structures provide a basis for the previous numerous observations of a biphasic dependence of the rate of PLA2 catalyzed hydrolysis of zwitterionic glycerophospholipids in the presence of bile salts. The rising or activation phase is consistent with enhanced binding and activation of the bound PLA2 by the bile salt induced anionic charge in a zwitterionic interface. The falling or inhibitory phase can be explained by the formation of a catalytically inert stoichiometric complex between PLA2 and any bile salts in which it forms a stable complex. The model provides new insight into the regulatory role that specific PLA2-bile salt interactions are likely to play in fat metabolism.

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Pancreatic porcine phospholipase A2 catalyzed hydrolysis of phosphatidylcholine in lecithin-bile salt mixed micelles: Kinetic studies in a lecithin-sodium cholate system

Cited by 26 publications

References 30 publications

Interações químico-fisiolóficas entre acidificantes, probióticos, enzimas e lisofosfolipídios na digestão de leitões

Interações químico-fisiolóficas entre acidificantes, probióticos, enzimas e lisofosfolipídios na digestão de leitões

Characterization of the kinetics of phospholipase C activity toward mixed micelles of sodium deoxycholate and dimyristoylphosphatidylcholine

Structural Basis for Bile Salt Inhibition of Pancreatic Phospholipase A2

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