Catalytic properties of mouse carbonic anhydrase V.
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Heck RW, Tanhauser SM, Manda R, Tu C, Laipis PJ, Silverman DN
Catalytic properties of mouse carbonic anhydrase V.
J Biol Chem. 1994 Oct 7;269(40):24742-6.
- PubMed ID
- 7929150 [ View in PubMed]
- Abstract
A cDNA encoding the mouse carbonic anhydrase V gene was isolated by reverse transcription and polymerase chain reaction from BALB/c mouse liver mRNA. Vectors containing the full coding sequence as well as two different NH2-terminal truncated genes expressed enzymatically active protein in Escherichia coli. The carbonic anhydrase V produced by a vector containing the full coding sequence, which includes a possible NH2-terminal mitochondrial targeting signal, was proteolytically processed by E. coli and contained several amino-terminal ends. The two NH2-terminal truncated vectors deleted, respectively, 1) the 29-amino acid putative targeting sequence and 2) 51 amino acids, yielding a protein equivalent to a carbonic anhydrase (CA) V isolated from mouse liver mitochondria; and both vectors produced homogeneous protein fractions. These latter two forms of CA V had identical steady-state constants for the hydration of CO2, with maximal values of kcat/Km at 3 x 10(7) M-1 s-1 and kcat at 3 x 10(5) s-1 with an apparent pKa for catalysis of 7.4 determined from kcat/Km. In catalytic properties, mouse CA V is closest to CA I; however, in inhibition by acetazolamide, ethoxzolamide, and cyanate, CA V is very similar to CA II. Mouse CA V has a tyrosine at position 64, where the highly active isozyme II has histidine serving as a proton shuttle in the catalytic pathway. Investigation of a site-specific mutant of CA V containing the replacement Tyr64-->His showed that the unique kinetic properties of CA V are not due to the presence of tyrosine at position 64.
DrugBank Data that Cites this Article
- Drug Targets
Drug Target Kind Organism Pharmacological Action Actions Ethoxzolamide Carbonic anhydrase 1 Protein Humans YesInhibitorDetails