Chapter

Enzimas proteolíticas: Aplicações biotecnológicas

In book: Enzimas em biotecnologia: produção, aplicações e mercado, Edition: 1, Chapter: 11, Publisher: Editora Interciência, pp.273-287

ABSTRACT As peptidases, cujo estudo iniciou-se nos fins do século XVI, impulsionado pelo interesse na anatomia e fisiologia do sistema digestivo, foram o primeiro grupo de enzimas com aplicações tecnológicas. Esta enzimas eram usadas no preparo de queijo, na formulação de detergentes e no tratamento do couro. A relevância bioquímica deste grupo de enzi-mas, rico em diversidade estrutural e mecanismos de ação, reflete-se, atualmente, na im-portância qualitativa e quantitativa das suas aplicações como enzimas industriais e especi-ais. As peptidases são hoje utilizadas nas indústria de detergentes, de têxteis, de alimen-tos, farmacêutica e analítica, em usos tão diversos como a sua recente aplicação nos proce-dimentos de análise de proteínas com técnicas proteômicas. Além disto, em consequên-cia do papel bioquímico das peptidases em vias metabólicas e em vias de sinalização celu-lar, cresce o interesse pelos inibidores destas enzimas e seu uso como produtos terapêuti-cos de última geração. Este capítulo apresenta alguns aspectos das peptidases, sua impor-tância biotecnológica e suas aplicações em diferentes segmentos industriais. INTRODUÇÃO As peptidases, peptídeo hidrolases ou proteases são enzimas hidrolíticas que clivam li-gações peptídicas nas proteínas e fragmentos de proteínas (BARRETT, 1994; BARRETT et alii, 2001). Elas têm presença universal entre os seres vivos e respondem 1ª prova 269 11 por cerca de 2% do total de proteínas presentes em todos os organismos, em vias meta-bólicas e de vias de sinalização celular. Adicionalmente, muitos microrganismos secre-tam peptidases para o meio externo com a finalidade de degradar proteínas cujos produtos de hidrólise são fontes de carbono e nitrogênio para o seu crescimento. Como as peptidases industriais, extraídas de plantas (papaína, bromelina, ficina) e de animais (peptidases digestivas) não atendem a demanda comercial, as peptidases mi-crobianas passaram a ter grande relevância industrial. A produção industrial de pepti-dases por microrganismos é favorecida pela facilidade de manipulação genética, diver-sidade genética e pequeno tempo de geração (RAO et alii, 1998).

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    ABSTRACT: Peptidases (often termed proteases) are of great relevance to biology, medicine, and biotechnology. This practical importance creates a need for an integrated source of information about peptidases. In the MEROPS database (www.merops.ac.uk), peptidases are classified by structural similarities in the parts of the molecules responsible for their enzymatic activity. They are grouped into families on the basis of amino acid sequence homology, and the families are assembled into clans in light of evidence that they share common ancestry. The evidence for clan-level relationships usually comes from similarities in tertiary structure, but we suggest that secondary structure profiles may also be useful in the future. The classification forms a framework around which a wealth of supplementary information about the peptidases is organized. This includes images of three-dimensional structures, alignments of matching human and mouse ESTs, comments on biomedical relevance, human and other gene symbols, and literature references linked to PubMed. For each family, there is an amino acid sequence alignment and a dendrogram. There is a list of all peptidases known from each of over 1000 species, together with summary data for the distributions of the families and clans throughout the major groups of organisms. A set of online searches provides access to information about the location of peptidases on human chromosomes and peptidase substrate specificity.
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