TY - JOUR
T1 - Kinetics of cleavage of intra- and extraceIlular simian virus 40 DNA with the enediyne anticancer drug C-1027
AU - Kirk, Christopher A.
AU - Goodisman, Jerry
AU - Beerman, Terry A.
AU - Gawron, Loretta S.
AU - Dabrowiak, James C.
N1 - Funding Information:
We wish to thank Dr. T. Otani of the Taiho Pharmaceutical Co. for samples of C-1027. This work was in part supported by a Shannon Award from the NIH (GM459241 to J.C.D. Support for T.A.B. was provided by the American Cancer Society (DHP-133) and the National Cancer Institute (CA 16056).
PY - 1997/1/31
Y1 - 1997/1/31
N2 - A kinetic analysis of cleavage of simian virus DNA (SV40 DNA) inside and outside green monkey BSC-1 cells by the enediyne-protein antibiotic C-1027 and its free chromophore is described. Information on rate constants was obtained by fitting populations of forms I (closed circular DNA), II (nicked circular DNA) and III (linear DNA) of SV40 DNA as a function of drug concentration to a kinetic model which includes: cutting of form I to give form II with rate constant k1, cutting of form I to give form III with rate constant k4, and cutting of form II to give form III with rate constant k2. The ratio of single-strand (ss) to double-strand (ds) cutting for the holoantibiotic and the free chromophore, k1/k4, is approximately 1.8 for extracellular SV40 DNA. For intracellular DNA and extracellular DNA which has been post-treated with putrescine, ds cutting is much more probable, with k4 about four times as large as k1. This observation suggests that amine groups present in the cell are able to convert abasic sites opposite an ss break into a ds break in SV40 chromatin. The overall rate of cleavage of form-I DNA inside the cell is much larger than the rate outside, the sum k1 + k4 being about three times as large for intracellular DNA as for extracellular DNA.
AB - A kinetic analysis of cleavage of simian virus DNA (SV40 DNA) inside and outside green monkey BSC-1 cells by the enediyne-protein antibiotic C-1027 and its free chromophore is described. Information on rate constants was obtained by fitting populations of forms I (closed circular DNA), II (nicked circular DNA) and III (linear DNA) of SV40 DNA as a function of drug concentration to a kinetic model which includes: cutting of form I to give form II with rate constant k1, cutting of form I to give form III with rate constant k4, and cutting of form II to give form III with rate constant k2. The ratio of single-strand (ss) to double-strand (ds) cutting for the holoantibiotic and the free chromophore, k1/k4, is approximately 1.8 for extracellular SV40 DNA. For intracellular DNA and extracellular DNA which has been post-treated with putrescine, ds cutting is much more probable, with k4 about four times as large as k1. This observation suggests that amine groups present in the cell are able to convert abasic sites opposite an ss break into a ds break in SV40 chromatin. The overall rate of cleavage of form-I DNA inside the cell is much larger than the rate outside, the sum k1 + k4 being about three times as large for intracellular DNA as for extracellular DNA.
KW - Intracellular DNA cleavage
KW - Kinetic analysis
KW - Kinetic theory
KW - Rate constants
UR - http://www.scopus.com/inward/record.url?scp=0030937998&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030937998&partnerID=8YFLogxK
U2 - 10.1016/S0301-4622(96)02217-X
DO - 10.1016/S0301-4622(96)02217-X
M3 - Article
C2 - 9108692
AN - SCOPUS:0030937998
SN - 0301-4622
VL - 63
SP - 201
EP - 209
JO - Biophysical Chemistry
JF - Biophysical Chemistry
IS - 2-3
ER -