TY  - JOUR
A1  - Schwerdtfeger, Klaus
A1  - Woenckhaus, Christoph
A1  - Parker, David M.
A1  - Holbrook, John J.
T1  - Coenzyme binding at different ionization states of cytoplasmic and mitochondrial malate dehydrogenase
T2  - Zeitschrift für Naturforschung, C
N2  - pH-titrations with NADH show two ionizable groups in mitochondrial and cytoplasmic malate dehydrogenase, the first with a pKa in the range 6.8 -8.3 for the mitochondrial and 6.4-7.8 for the cytoplasmic enzyme, the second with a lower limit at 10.2 resp. 11. Comparison with bis-(dihydronicotinamide)-dinucleotide and dihydronicotina-mide-ribosyl-P2-ribose-pyrophosphate instead of NADH indicates that the second alkaline ionization is caused by a residue placed near the adenine binding site of the active centre of the two isoenzymes. Binding studies with NADH and NAD+ give evidence for the participation of a group in the mitochondrial enzyme with pKa 6.8, deprotonation of which is necessary for detectable association of NAD+. In contrast the fixation of NAD+ to the cytoplasmic enzyme is independent of pH.
KW  - Malate Dehydrogenases
KW  - Ionization State
KW  - Coenzyme Binding
Y1  - 2014
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/71937
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-719371
SN  - 0939-5075
SN  - 1865-7125
VL  - 37.1982
IS  - 5-6
SP  - 547
EP  - 549
PB  - Verlag der Zeitschrift für Naturforschung
CY  - Tübingen
ER  -