TY - JOUR
T1 - Are all nucleotidyl transferases metalloenzymes?
AU - Valenzuela, Pablo
AU - Morris, Robert W.
AU - Faras, Anthony
AU - Levinson, Warren
AU - Rutter, William J.
PY - 1973/8/6
Y1 - 1973/8/6
N2 - Previous studies (1,2) have shown that DNA polymerases (sea urchin and E. coli I) and E. coli RNA polymerases are zinc metalloproteins. We report here that DNA-dependent RNA polymerases I and II from rat liver, I, II and III from sea urchin, and RNA-dependent DNA polymerase (reverse transcriptase) from Rous sarcoma virus are inhibited by pre-incubation with the chelating agent, o-phenanthroline. These enzymes are not affected by pre-incubation with the related compound, m-phenanthroline, which is not a metal chelating agent. The data suggest that, in addition to Mg++ or Mn++, the enzymes require a tightly bound metal ion (possibly zinc) for catalytic activity. The DNA-terminal transferase is also inhibited by o-phenanthroline but not m-phenanthroline (3). On the other hand, we found that tRNA-nucleotidyl transferases from Rous sarcoma virions and yeast are not affected by either o- or m-phenanthroline. These observations suggest that many but not all nucleotidyl transferases are metallo-enzymes.
AB - Previous studies (1,2) have shown that DNA polymerases (sea urchin and E. coli I) and E. coli RNA polymerases are zinc metalloproteins. We report here that DNA-dependent RNA polymerases I and II from rat liver, I, II and III from sea urchin, and RNA-dependent DNA polymerase (reverse transcriptase) from Rous sarcoma virus are inhibited by pre-incubation with the chelating agent, o-phenanthroline. These enzymes are not affected by pre-incubation with the related compound, m-phenanthroline, which is not a metal chelating agent. The data suggest that, in addition to Mg++ or Mn++, the enzymes require a tightly bound metal ion (possibly zinc) for catalytic activity. The DNA-terminal transferase is also inhibited by o-phenanthroline but not m-phenanthroline (3). On the other hand, we found that tRNA-nucleotidyl transferases from Rous sarcoma virions and yeast are not affected by either o- or m-phenanthroline. These observations suggest that many but not all nucleotidyl transferases are metallo-enzymes.
UR - http://www.scopus.com/inward/record.url?scp=0015831798&partnerID=8YFLogxK
U2 - 10.1016/0006-291X(73)90196-4
DO - 10.1016/0006-291X(73)90196-4
M3 - Article
C2 - 4125981
AN - SCOPUS:0015831798
VL - 53
SP - 1036
EP - 1041
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 3
ER -