Kinetic characterization of the pyruvate and oxoglutarate dehydrogenase complexes from human heart.
Acta Biochim Pol
; 37(1): 135-9, 1990.
Article
in En
| MEDLINE
| ID: mdl-2087902
ABSTRACT
The Michaelis constant values for the highly purified pyruvate dehydrogenase complex (PDC) from human heart are 25, 13 and 50 microM for pyruvate, CoA and NAD, respectively. Acetyl-CoA produces a competitive inhibition of PDC (Ki = 35 microM) with respect to CoA, whereas NADH produces the same type of inhibition with respect to NAD (Ki = 36 microM). The oxoglutarate dehydrogenase complex (OGDC) from human heart has active sites with two different affinities for 2-oxoglutarate ([S]0.5 of 30 and 120 microM). ADP (1 mM) decreases the [S]0.5 values by a half. The inhibition of OGDC (Ki = 81 microM) by succinyl-CoA is of a competitive type with respect to CoA (Km = 2.5 microM), whereas that of NADH (Ki = 25 microM) is of a mixed type with respect to NAD (Km = 170 microM).
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Pyruvate Dehydrogenase Complex
/
Ketoglutarate Dehydrogenase Complex
/
Myocardium
Limits:
Adult
/
Humans
/
Male
Language:
En
Journal:
Acta Biochim Pol
Year:
1990
Document type:
Article