PMID- 6882473
OWN - NLM
STAT- MEDLINE
DCOM- 19830909
LR  - 20190623
IS  - 0006-2952 (Print)
IS  - 0006-2952 (Linking)
VI  - 32
IP  - 15
DP  - 1983 Aug 1
TI  - Protein carboxyl-O-methyltransferase activity in cultured C-1300 neuroblastoma 
      cells.
PG  - 2339-43
AB  - Protein carboxylmethyltransferase (PCM) has been identified in a variety of 
      tissues derived from neural crest anlage, including in vivo C-1300 murine 
      neuroblastoma (MNB). These observations have stimulated interest in further 
      defining the role of PCM as a potential modulator of neoplastic cell behavior. 
      The subcellular distribution and kinetic behavior of PCM have been characterized 
      in a tissue culture line derived from the C-1300 murine neuroblastoma (clone 
      NB41A3). The specific and total activities of PCM in the presence and absence of 
      exogenous substrate were determined in subcellular fractions of MNB cells 
      prepared by differential centrifugation. In the presence of exogenous substrate 
      (+ gelatin), 40% of the total PCM activity was present in the 100,000 g 
      supernatant fraction and 41% in the 800 g particulate fraction, whereas the 
      higher specific activity of PCM was present in the 100,000 g supernatant 
      fraction. Enzyme activity measured in the absence of gelatin, which reflects the 
      concentration of endogenous methyl acceptor proteins in a cell fraction, was 
      negligible. This activity represented less than 1.6 and 0.4% of the total PCM 
      activity present in the 800 g particulate and 100,000 g soluble fractions 
      respectively. Cytosolic PCM had an apparent Km of 13.9 x 10(-6) M for AdoMet and 
      a Vmax of 33 pmoles per min per mg protein. Cytoplasmic PCM was inhibited 
      competitively by S-adenosylhomocysteine (Ki equal 0.2 microM). These data 
      demonstrate that the specific activity of PCM was greatest in the soluble 
      component of subcellular fractions prepared from cultured MNB cells. This 
      distribution pattern of PCM is similar to that observed in the C-1300 MNB tumor 
      grown in situ and in non-malignant tissues. In contrast to the latter tissues, 
      cultured MNB cells exhibited low PCM activity when assayed in the absence of 
      exogenous substrate.
FAU - O'Leary, M
AU  - O'Leary M
FAU - Hansen, J A
AU  - Hansen JA
FAU - Mirkin, B L
AU  - Mirkin BL
FAU - O'Dea, R F
AU  - O'Dea RF
LA  - eng
GR  - HL-00565/HL/NHLBI NIH HHS/United States
GR  - NS-17194/NS/NINDS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - England
TA  - Biochem Pharmacol
JT  - Biochemical pharmacology
JID - 0101032
RN  - 66753-47-7 (A9145C)
RN  - 979-92-0 (S-Adenosylhomocysteine)
RN  - EC 2.1.1.- (Protein Methyltransferases)
RN  - EC 2.1.1.- (Protein O-Methyltransferase)
RN  - K72T3FS567 (Adenosine)
RN  - W2U467CIIL (sinefungin)
SB  - IM
MH  - Adenosine/analogs & derivatives/pharmacology
MH  - Animals
MH  - Cells, Cultured
MH  - Kinetics
MH  - Mice
MH  - Neuroblastoma/*enzymology
MH  - Protein Methyltransferases/*metabolism
MH  - Protein O-Methyltransferase/*metabolism
MH  - S-Adenosylhomocysteine/pharmacology
MH  - Tissue Distribution
EDAT- 1983/08/01 00:00
MHDA- 1983/08/01 00:01
CRDT- 1983/08/01 00:00
PHST- 1983/08/01 00:00 [pubmed]
PHST- 1983/08/01 00:01 [medline]
PHST- 1983/08/01 00:00 [entrez]
AID - 0006-2952(83)90183-1 [pii]
AID - 10.1016/0006-2952(83)90183-1 [doi]
PST - ppublish
SO  - Biochem Pharmacol. 1983 Aug 1;32(15):2339-43. doi: 10.1016/0006-2952(83)90183-1.