Separation of two microbial transglutaminase isomers from Streptomyces mobaraensis using pH-mediated cation exchange chromatography and their characterization

Mingfei Jin, Zhongshan Chen, Zhizhen Wang, Jing Huang, Zhongyi Chang, Hongliang Gao*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Microbial transglutaminase (MTGase) derived from Streptomyces mobaraensis has been widely used in the food, biotechnology and medicine fields. The lot-to-lot consistency and product stability of MTGase must be ensured. The structure and charge variants of MTGase can influence its bioactivity. In this study, MTGase isomers (MTG I1 and MTG I2) were found during the separation of MTGase by pH-mediated cation-exchange chromatography. MTG I1 and MTG I2 had the same molecular weight and N-terminal amino acid sequences, but they showed charge heterogeneity. The affinity of MTG I2 for substrates was higher than that of MTG I1, and the thermal stability and the acid-base tolerance of MTG I1 were significantly higher than that of MTG I2. Therefore, the ratio of MTG I1/MTG I2 was positively correlated with the stability of MTGase. The buffer pH and the ionic strength of the eluent had significant effects on the separation of MTG I1 and MTG I2, and the elution gradient steepness and column load showed little effect on the separation of the MTG I1 and MTG I2 peaks. We built a stable and repeatable separation method for MTG I1 and MTG I2. MTG I1 could transform into MTG I2, but MTG I2 was unable to transform into MTG I1, making the transformation of MTG I1 to MTG I2 was irreversible. When MTG I2 was removed from the MTGase, a portion of the MTG I1 could transform into MTG I2. Therefore, one way to increase the stability of MTGase was to reduce the transformation of MTG I1 to MTG I2.

Original languageEnglish
Pages (from-to)111-118
Number of pages8
JournalJournal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences
Volume1097-1098
DOIs
StatePublished - 15 Oct 2018

Keywords

  • Charge heterogeneity
  • Isomers
  • Microbial transglutaminase (MTGase)
  • Peak splitting
  • Stability
  • Transformation

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