Doctoral Dissertations


Ke Li

Keywords and Phrases

Cataract; Glycosylation; Lanosterol; Monoclonal antibodies; Poly (ethylene) glycol; α-crystallin


"Solubility is a critical factor of protein-based drugs during processing and patient administration. This study focused on two aspects of solubility: one was the poly (ethylene) glycol (PEG) precipitation of monoclonal antibodies (mAbs) and another was crystallins aggregation that is associated with cataracts. Protein precipitation by PEG is a common technique for downstream processing. The effects of pH, ionic strength and the exclude volume effect on the protein precipitation by PEG were extensively studied, but the effects of glycosylation on protein precipitation by PEG has not been examined. Protein aggregation is not only a problem in downstream processing, but it is also related to some diseases. In 2015, lanosterol and 25-hydroxycholesterol were reported to dissolve protein aggregates in cataract lenses. Researchers focused on dissolution of lens protein aggregates, but the effects of those two sterols on the formation of aggregates were not investigated. The objectives of this dissertation were: 1) to determine the role of glycosylation in the precipitation of mAbs by PEG, and 2) to study the effects of lanosterol and 25-hydroxycholesterol on α-crystallin aggregation. The glycosylated mAbs showed higher solubility than non-glycosylated mAbs. It was found that available solubility models cannot correlate the effect of glycosylation. Lanosterol and 25- hydroxycholesterol failed to prevent α-crystallin aggregation. A concentration of 125pM of the two sterols promoted the aggregation of α-crystallin and of the α/γ complex possible by serving as nucleation sites. The secondary and tertiary structures of α-crystallin were not affected upon addition of the two sterols. The α-crystallin chaperon activity and the capacity of binding with Cu2+ were not affected either"--Abstract, page iv.


Forciniti, Daniel

Committee Member(s)

Ludlow, Douglas K.
Liang, Xinhua
Rezaei, Fateme
Wang, Risheng


Chemical and Biochemical Engineering

Degree Name

Ph. D. in Chemical Engineering


Missouri University of Science and Technology

Publication Date

Summer 2021

Journal article titles appearing in thesis/dissertation

  • Poly (ethylene) glycol (peg) precipitation of glycosylated and non-glycosylated monoclonal antibodies
  • Solubility of lanosterol in organic solvents and in water-alcohol mixtures at 101.8 kpa
  • Is it possible to prevent aggregation of alpha crystallin by adding sterols?


xiii, 145 pages

Note about bibliography

Includes bibliographic references.


© 2021 Ke Li, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Thesis Number

T 11906

Electronic OCLC #