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. Author manuscript; available in PMC: 2013 Jul 22.
Published in final edited form as: FEBS J. 2011 Aug 24;278(18):3319–3336. doi: 10.1111/j.1742-4658.2011.08248.x

Fig. 4. Recombinant Sra-HSP-17s lack the molecular chaperone activity in vitro.

Fig. 4

Neither rSra-HSP-17.1 nor rSra-HSP-17.2 were able to reduce the thermally aggregated proteins: (A): citrate synthase (CS) from porcine heart, provided in 2.2 M (NH4)2SO4, 6 mM phosphate, 0.5 mM citrate (Sigma) used in concentration of 75 μg/mL at 45 °C or (B): malate dehydrogenase (MDH) from porcine heart provided in ammonium sulfate (sigma) used at a concentration of 41.5 μg/mL at 48 °C. For both substrates the molar ratios (HSP/substrate) were 1:10 and 1:20. Absorbance was recorded at O.D. 360 nm for insulin and MDH and at O.D 320 nm for CS aggregations each 5 min. for 40 min using ultrospec 2000 spectrophotometer (Pharmacia, Biotech.) for 40 min in 1 mL semi microquartz tubes. (C): Both rSra-HSP-17s showed no inhibition of chemically-induced insulin aggregation at 37 °C in a molar ratio (HSP/insulin) of 1:2.5, 1:5 and 1:10. The bovine pancreas insulin (250 μg/mL), provided in 25mM HEPES pH 8.2 (Sigma), induced for aggregation by 0.02 M DTT.