Spectrophotometric assay for serum glutathione transferase: a re-examination.

Author(s): Fabrini R, Bocedi A, Massoud R, Federici G, Ricci G

Publication: Clin Biochem, 2012, Vol. 45, Page 668-71

PubMed ID: 22391028 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effects of storage duration at 37 degrees C, substrate additives, specimen pH and quantification method on the levels of GST in spiked serum.

   Summary of Findings:

   When GST activity was quantified using a spectrophotometer, the basal levels were much higher then when measured with ELISA or radioimmunoassay (RIA). Further, GST activity measured by spectrophotometer was increased when serum was spiked with 5 mM glutathione (GSH) instead of 1 mM GSH, but this increase was <20% when 10 ug/mL of purified GSTP1 GST pi (GSTP1-1), alpha (GSTA1-1) or mu (GSTM2-2) were added. When GSTP1-1 or GSTM2-2 were incubated with serum at 37 degrees C, the activity was completely lost after 2 and 48 h, respectively. In contrast, when GSTA1-1 was incubated with serum at 37 degrees C, only 50% of the activity was lost after 4 days. GST activity measured by spectrophotometer increased when pH was increased. The authors conclude that the spectrophotometric method is not suitable for quantification of GST activity.

   Biospecimens

   • Bodily Fluid - Serum

   Preservative Types

   • None (Fresh)

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   Protein	ELISA
   Protein	Spectrophotometry
   Protein	Radioimmunoassay

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Storage	Storage duration	0 min 5 min 15 min 30 min 1 h 6 h 12 h 24 h 30 h 36 h 5 days 12 days 14 days 15 days
   Biospecimen Aliquots and Components	Biospecimen components	1 mM GSH 5 mM GSH GSTP1-1 GSTA1-1 GSTM2-2
   Spectrophotometry Specific	Technology platform	RIA ELISA
   Biospecimen Aliquots and Components	pH	5.3 5.7

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