Expression of functional recombinant human lysozyme in transgenic rice cell culture

Jianmin Huang, Liying Wu, Dorice Yalda, Yuriko Adkins, Shannon Kelleher, Michael Crane, Bo Lonnerdal, Raymond L. Rodriguez, Ning Huang

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98 Scopus citations


Using particle bombardment-mediated transformation, a codon-optimized synthetic gene for human lysozyme was introduced into the calli of rice (Oryza sativa) cultivar Taipei 309. The expression levels of recombinant human lysozyme in the transformed rice suspension cell culture approached approximately 4% of total soluble protein. Recombinant human lysozyme was purified to greater than 95% homogeneity using a two-step chromatography process. Amino acid sequencing verified that the N-terminus of the mature recombinant human lysozyme was identical to native human lysozyme. This indicates that the rice RAmy3D signal peptide was correctly cleaved off from the human lysozyme preprotein by endogenous rice signal peptidase. Recombinant human lysozyme was found to have the same molecular mass, isoelectric point and specific activity as native human lysozyme. The bactericidal activity of recombinant human lysozyme was determined by turbidimetric assay using Micrococcus lysodeikticus in 96-well microtiter plates. The bactericidal activity of lysozyme on Gram-negative bacteria was examined by adding purified lysozyme to mid-log phase cultures of E. coli strain JM109. In this study, significant bactericidal activity was observed after E. coli cells were exposed to recombinant human lysozyme for 60 min. Both native and recombinant human lysozyme displayed the same thermostability and resistance to degradation by low pH. The potential for using rice-derived lysozyme as an antimicrobial food supplement, particularly for infant formula and baby foods, is discussed.

Original languageEnglish (US)
Pages (from-to)229-239
Number of pages11
JournalTransgenic Research
Issue number3
StatePublished - Jul 2 2002

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Animal Science and Zoology
  • Genetics
  • Agronomy and Crop Science


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