ABSTRACT
It has been reported that pulse proteolysis may be used to investigate protein unfolding kinetics in cell lysate. However, the method has not become popular and we could not judge whether or not it is effective for protein folding study. In this work, we examined the folding and unfolding kinetics of a protein and its variants without purification by pulse proteolysis. The unfolding and refolding rates of the unpurified proteins were similar to those of the purified proteins determined by pulse proteolysis and circular dichroism. Furthermore, because we used a super-stable subtilisin as a protease, we could evaluate the kinetics at 50°C. The present work demonstrates the validity of pulse proteolysis for folding and unfolding studies of unpurified proteins.
Subject(s)
Protein Refolding , Protein Unfolding , Proteolysis , Ribonuclease H/chemistry , Subtilisin/chemistry , Thermococcus/metabolism , Circular Dichroism , Protein Structure, Tertiary , Ribonuclease H/analysis , Subtilisin/analysisABSTRACT
Several studies have shown the predictive value of elevated serum alkaline phosphatase (ALP) level in multiple myeloma (MM) patients treated with bortezomib (BTZ). We assessed the relationship between changes in ALP levels during treatment and response. Thirty patients treated with BTZ in our hospital were analyzed retrospectively. Of the patients analyzed, 12 were male, median age was 62 years (42-86), and 11 had a history of prior chemotherapy. Eighteen patients were treated with BTZ alone or in combination with dexamethasone, while the others were treated with a combination regimen employing an alkylating agent. Seven patients had undergone autologous stem cell transplantation following BTZ therapy. Ten of 28 patients showed ALP elevation of 25% or more from the baseline at 3 weeks, and 14 of the 28 had this finding at 6 weeks. Four of 5 patients who had achieved VGPR or more showed ALP elevation of 25% or more at 3 weeks, and all five had this finding by 6 weeks. No patient without ALP elevation achieved VGPR or a better response. ALP elevation exceeding 25% from the baseline by day 42 is significantly associated with a treatment response better than VGPR (p=0.019). In conclusion, ALP elevation during BTZ treatment is a valuable prognostic marker.
