Capillary electrophoretic analysis of μ- and m-calpain using fluorescently labeled casein substrates

Xuelin Gu, Georgianna Whipple-VanPatter, Mary O'Dwyer, Michael Zeece

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Calpains are unique calcium-dependent thiol proteases that have been proposed to participate in a number of physiological processes including signal transduction and protein turnover in skeletal muscle. Calpains exist in two major forms. Interestingly, the two forms of protease show no significant difference in their action on various substrates. The only demonstrable difference in their activity involves the concentration of calcium required for activation. Both μ- and m-calpains typically achieve half maximal activation at 50 μM and 0.7 mM calcium, respectively. The focus of this study was to examine the action of both forms of calpain on casein substrates and assess whether any differences could be observed in the resulting peptide finger print using capillary electrophoresis. Purified μ- and m-calpain were incubated for various lengths of time with Oregon Green labeled αs- and β-casein. The reactions were stopped with sodium dodecyl sulfate (SDS) and products separated by capillary electrophoresis in micellar electrokinetic capillary chromatography (MEKC) mode using laser-induced fluorescence (LIF) detection. Comparison of the electropherograms showed no difference in the peptide profile for either enzyme. However, it was found that β-casein was hydrolyzed more extensively than αs-casein, by both enzymes. Capillary electrophoresis was found to be a very sensitive technique for detection of calpain activity. Using β-casein as substrate, the CE approach was able to detect 2-3 ng of calpain activity. The results also suggest that capillary electrophoresis is a useful tool for proteolytic investigations of protein structure.

Original languageEnglish (US)
Pages (from-to)2336-2342
Number of pages7
JournalELECTROPHORESIS
Volume22
Issue number11
DOIs
StatePublished - Aug 8 2001

Fingerprint

Calpain
Caseins
Capillary electrophoresis
Capillary Electrophoresis
Substrates
Calcium
Peptide Hydrolases
Chemical activation
Micellar Electrokinetic Capillary Chromatography
Physiological Phenomena
Signal transduction
Peptides
Enzymes
Laser modes
Chromatography
Sulfhydryl Compounds
Sodium Dodecyl Sulfate
Fingers
Muscle
Signal Transduction

Keywords

  • Calpain
  • Capillary electrophoresis
  • Casein
  • Proteolytic specificity

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Clinical Biochemistry

Cite this

Capillary electrophoretic analysis of μ- and m-calpain using fluorescently labeled casein substrates. / Gu, Xuelin; Whipple-VanPatter, Georgianna; O'Dwyer, Mary; Zeece, Michael.

In: ELECTROPHORESIS, Vol. 22, No. 11, 08.08.2001, p. 2336-2342.

Research output: Contribution to journalArticle

Gu, Xuelin ; Whipple-VanPatter, Georgianna ; O'Dwyer, Mary ; Zeece, Michael. / Capillary electrophoretic analysis of μ- and m-calpain using fluorescently labeled casein substrates. In: ELECTROPHORESIS. 2001 ; Vol. 22, No. 11. pp. 2336-2342.
@article{6cbefad81dda426182a27c8e336c1d95,
title = "Capillary electrophoretic analysis of μ- and m-calpain using fluorescently labeled casein substrates",
abstract = "Calpains are unique calcium-dependent thiol proteases that have been proposed to participate in a number of physiological processes including signal transduction and protein turnover in skeletal muscle. Calpains exist in two major forms. Interestingly, the two forms of protease show no significant difference in their action on various substrates. The only demonstrable difference in their activity involves the concentration of calcium required for activation. Both μ- and m-calpains typically achieve half maximal activation at 50 μM and 0.7 mM calcium, respectively. The focus of this study was to examine the action of both forms of calpain on casein substrates and assess whether any differences could be observed in the resulting peptide finger print using capillary electrophoresis. Purified μ- and m-calpain were incubated for various lengths of time with Oregon Green labeled αs- and β-casein. The reactions were stopped with sodium dodecyl sulfate (SDS) and products separated by capillary electrophoresis in micellar electrokinetic capillary chromatography (MEKC) mode using laser-induced fluorescence (LIF) detection. Comparison of the electropherograms showed no difference in the peptide profile for either enzyme. However, it was found that β-casein was hydrolyzed more extensively than αs-casein, by both enzymes. Capillary electrophoresis was found to be a very sensitive technique for detection of calpain activity. Using β-casein as substrate, the CE approach was able to detect 2-3 ng of calpain activity. The results also suggest that capillary electrophoresis is a useful tool for proteolytic investigations of protein structure.",
keywords = "Calpain, Capillary electrophoresis, Casein, Proteolytic specificity",
author = "Xuelin Gu and Georgianna Whipple-VanPatter and Mary O'Dwyer and Michael Zeece",
year = "2001",
month = "8",
day = "8",
doi = "10.1002/1522-2683(20017)22:11<2336::AID-ELPS2336>3.0.CO;2-N",
language = "English (US)",
volume = "22",
pages = "2336--2342",
journal = "Electrophoresis",
issn = "0173-0835",
publisher = "Wiley-VCH Verlag",
number = "11",

}

TY - JOUR

T1 - Capillary electrophoretic analysis of μ- and m-calpain using fluorescently labeled casein substrates

AU - Gu, Xuelin

AU - Whipple-VanPatter, Georgianna

AU - O'Dwyer, Mary

AU - Zeece, Michael

PY - 2001/8/8

Y1 - 2001/8/8

N2 - Calpains are unique calcium-dependent thiol proteases that have been proposed to participate in a number of physiological processes including signal transduction and protein turnover in skeletal muscle. Calpains exist in two major forms. Interestingly, the two forms of protease show no significant difference in their action on various substrates. The only demonstrable difference in their activity involves the concentration of calcium required for activation. Both μ- and m-calpains typically achieve half maximal activation at 50 μM and 0.7 mM calcium, respectively. The focus of this study was to examine the action of both forms of calpain on casein substrates and assess whether any differences could be observed in the resulting peptide finger print using capillary electrophoresis. Purified μ- and m-calpain were incubated for various lengths of time with Oregon Green labeled αs- and β-casein. The reactions were stopped with sodium dodecyl sulfate (SDS) and products separated by capillary electrophoresis in micellar electrokinetic capillary chromatography (MEKC) mode using laser-induced fluorescence (LIF) detection. Comparison of the electropherograms showed no difference in the peptide profile for either enzyme. However, it was found that β-casein was hydrolyzed more extensively than αs-casein, by both enzymes. Capillary electrophoresis was found to be a very sensitive technique for detection of calpain activity. Using β-casein as substrate, the CE approach was able to detect 2-3 ng of calpain activity. The results also suggest that capillary electrophoresis is a useful tool for proteolytic investigations of protein structure.

AB - Calpains are unique calcium-dependent thiol proteases that have been proposed to participate in a number of physiological processes including signal transduction and protein turnover in skeletal muscle. Calpains exist in two major forms. Interestingly, the two forms of protease show no significant difference in their action on various substrates. The only demonstrable difference in their activity involves the concentration of calcium required for activation. Both μ- and m-calpains typically achieve half maximal activation at 50 μM and 0.7 mM calcium, respectively. The focus of this study was to examine the action of both forms of calpain on casein substrates and assess whether any differences could be observed in the resulting peptide finger print using capillary electrophoresis. Purified μ- and m-calpain were incubated for various lengths of time with Oregon Green labeled αs- and β-casein. The reactions were stopped with sodium dodecyl sulfate (SDS) and products separated by capillary electrophoresis in micellar electrokinetic capillary chromatography (MEKC) mode using laser-induced fluorescence (LIF) detection. Comparison of the electropherograms showed no difference in the peptide profile for either enzyme. However, it was found that β-casein was hydrolyzed more extensively than αs-casein, by both enzymes. Capillary electrophoresis was found to be a very sensitive technique for detection of calpain activity. Using β-casein as substrate, the CE approach was able to detect 2-3 ng of calpain activity. The results also suggest that capillary electrophoresis is a useful tool for proteolytic investigations of protein structure.

KW - Calpain

KW - Capillary electrophoresis

KW - Casein

KW - Proteolytic specificity

UR - http://www.scopus.com/inward/record.url?scp=0034916375&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034916375&partnerID=8YFLogxK

U2 - 10.1002/1522-2683(20017)22:11<2336::AID-ELPS2336>3.0.CO;2-N

DO - 10.1002/1522-2683(20017)22:11<2336::AID-ELPS2336>3.0.CO;2-N

M3 - Article

C2 - 11504070

AN - SCOPUS:0034916375

VL - 22

SP - 2336

EP - 2342

JO - Electrophoresis

JF - Electrophoresis

SN - 0173-0835

IS - 11

ER -