Original Article

Journal of Plant Biochemistry and Biotechnology

, Volume 22, Issue 3, pp 261-268

Trypsin inhibitors in xoconostle seeds (Opuntia joconostle Weber.)

  • María Teresa Aguirrezabala-CámpanoAffiliated withFacultad de Agronomía-Laboratorio de Biotecnología, Universidad Autónoma de Nuevo León (UANL)
  • , Reyna Ivonne Torres-AcostaAffiliated withExperimental field General Terán del Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias
  • , Alejandro Blanco-LabraAffiliated withCentro de Investigación y de Estudios Avanzados del I. P. N. Unidad Irapuato
  • , Ma. Elizabeth Mediola-OlayaAffiliated withCentro de Investigación y de Estudios Avanzados del I. P. N. Unidad Irapuato
  • , Sugey Ramona Sinagawa-GarcíaAffiliated withFacultad de Agronomía-Laboratorio de Biotecnología, Universidad Autónoma de Nuevo León (UANL)
  • , Adriana Gutiérrez-DíezAffiliated withFacultad de Agronomía-Laboratorio de Biotecnología, Universidad Autónoma de Nuevo León (UANL)
  • , Jorge Ariel Torres-CastilloAffiliated withFacultad de Agronomía-Laboratorio de Biotecnología, Universidad Autónoma de Nuevo León (UANL) Email author 

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Abstract

Seed proteins recovered after heating a seed extract from Opuntia joconostle Weber (xoconostle, an acid cactus pear) were screened for different biochemical activities, detecting only trypsin-like inhibitory activity. Two trypsin-like inhibitor forms from seeds were separated by RP-HPLC and partially sequenced and characterized as an enriched mixture. They were evaluated for inhibition on several serine proteinases, but only trypsin-like inhibition was detected by the inhibitor extract. The two isolated forms, OjTI 1 and OjTI 2 showed low molecular weights of 4.26 and 4.17 kDa as determined by mass spectrometry. An enriched inhibitory fraction showed a high thermal stability by retaining the activity after heating the sample for 1 h at 90 °C, as well as after heating for at 120 °C under 1 kg/cm2 for 15 min at different pH values. Partial sequence of the two forms was determined by mass spectrometry indicating that they were similar and after alignments analysis they showed the highest similarity with the trypsin inhibitor from O. streptacantha and to a lesser extent to other trypsin inhibitors of the MEROPS database families. The inhibitory spectrum was evaluated against several digestive enzymes from pests and beneficial insects from several taxonomic orders.

Keywords

Cactaceae Xoconostle Trypsin inhibitor Heat resistant seed proteins Proteinase inhibitor