ABSTRACT
En las sociedades industrializadas se está reflexionando cada vez más sobre el impacto de la inseguridad alimentaria, entendida como la dificultad para asegurar la accesibilidad de una parte de la población a los recursos alimentarios suficientes para garantizar su subsistencia y bienestar. Con base en datos recogidos a partir de una investigación en curso en España, este artículo discute, por un lado, si la actual crisis económica está revirtiendo algunas de las tendencias positivas que el sistema agroalimentario industrial había favorecido, como la disminución de las diferencias sociales en el consumo y el derecho a la alimentación. Por otro lado, reflexiona acerca de la creciente precarización en las estrategias alimentarias y en el estado de salud de la población, así como sobre la necesidad de considerar la desigualdad social como variable explicativa de las diversas maneras de alimentarse.
This article analyzes the reasons why food insecurity in Spain must increasingly be understood as lack of access to sufficient food resources to guarantee the survival and wellbeing of part of the population. Using data collected in an ongoing research project, two possible causes for this are explored. First, it is argued that certain positive developments that seemed firmly established, such as recognition of the right to an adequate diet and the leveling out of social differences in food consumption, are now being reversed by the current economic crisis. Second, the analysis focuses on strategies people in precarious circumstances use to obtain food, their relationship to health, and the need to take social inequality into consideration as an explanatory variable in accounting for different ways of procuring daily sustenance.
Subject(s)
Cathepsin B/chemistry , Cysteine Proteinase Inhibitors/chemistry , Dipeptides/chemistry , Leucine/analogs & derivatives , Binding Sites , Cathepsin B/antagonists & inhibitors , Cathepsin B/metabolism , Computer Simulation , Cysteine Proteinase Inhibitors/metabolism , Hydrogen Bonding , Leucine/chemistry , Leucine/metabolism , Models, Molecular , Molecular Conformation , Monte Carlo Method , Structure-Activity RelationshipSubject(s)
Cysteine Endopeptidases/chemistry , Enzyme Precursors/chemistry , Plant Proteins/chemistry , Protein Structure, Secondary , Amino Acid Chloromethyl Ketones/chemistry , Amino Acid Sequence , Cathepsin B/chemistry , Computer Simulation , Crystallography, X-Ray , Cysteine Endopeptidases/genetics , Cysteine Proteinase Inhibitors , Enzyme Activation , Enzyme Precursors/genetics , Fruit , Hydrogen Bonding , Leucine/analogs & derivatives , Leucine/chemistry , Leupeptins/chemistry , Models, Molecular , Molecular Sequence Data , Mutation , Oligopeptides/chemistry , Papain/chemistry , Plant Proteins/genetics , Protein Processing, Post-Translational , Sequence Homology, Amino AcidABSTRACT
Cathepsin B was isolated from buffalo liver by salt fractionation, ion-exchange resin treatment, gel filtration and repeated ion-exchange chromatography using a linear salt gradient. The enzyme showed activity, against denatured hemoglobin (or ovalbumin), alpha-N-benzoyl-DL-arginine p-nitroanilide (BAPNA), and alpha-benzoyl-DL-arginine-naphthylamine (BANA). It inactivated buffalo muscle aldolase with a half life period of 21 min. The pH-activity profiles obtained for the digestion of hemoglobin (or ovalbumin) and aldolase inactivation by the enzyme were found to be different. The enzyme (mol wt 27,800 by SDS-PAGE) eluted in gel filtration with a molecular weight of 27,000 and a Stokes radius of 2.31 nm. The results showed buffalo cathepsin B to be a single-chain molecule. The N- and C-terminal amino acids of the enzyme were found to be leucine and aspartic acid, respectively. It contained 0.7% concanavalin A reactive neutral carbohydrate. The amino acid composition of buffalo cathepsin B was found to be similar to that of human liver cathepsin B. The optical properties of the buffalo enzyme were found consistent with its aromatic amino acid content. The isoionic pH of the enzyme was found to be 5.70 and the intrinsic viscosity was 3.48 ml/g whence the frictional ratio, f/f0 was computed to be 1.10 suggesting that the native enzyme conformation is compact and is globular in solution.