Replacement of C305 in heart/muscle-type isozyme of human carnitine palmitoyltransferase I with aspartic acid and other amino acids.
Liver- and heart/muscle-type isozymes of human carnitine palmitoyltransferase I (L- and M-CPTI, respectively) show a certain similarity in their amino acid sequences, and mutation studies on the conserved amino acids between these two isozymes often show essentially the same effects on their enzymatic properties. Earlier mutation studies on C305 in human M-CPTI and its counterpart residue, C304, in human L-CPTI showed distinct effects of the mutations, especially in the aspect of enzyme stability; however, simple comparison of these effects on the conserved Cys residue between L- and M-CPTI was difficult, because these studies were carried out using different expression systems and distinct amino acids as replacements. In the present study, we carried out mutation studies on the C305 in human M-CPTI using COS cells for the expression system. Our results showed that C305 was replaceable with aspartic acid but that substitution with other amino acids caused both loss of function and reduced expression.
Matsuo
Taisuke
T
Institute for Genome Research, University of Tokushima, Kuramotocho-3, Tokushima 770-8503, Japan.
Yamamoto
Atsushi
A
Yamamoto
Takenori
T
Otsuki
Kaoru
K
Yamazaki
Naoshi
N
Kataoka
Masatoshi
M
Terada
Hiroshi
H
Shinohara
Yasuo
Y
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000502:physiology*; D000596:Amino Acids / Q000235:genetics; D000818:Animals; D001224:Aspartic Acid / Q000235:genetics*; D019556:COS Cells; D002334:Carnitine O-Palmitoyltransferase / Q000235:genetics* / Q000378:metabolism; D002522:Chlorocebus aethiops; D003545:Cysteine / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D009206:Myocardium / Q000378:metabolism; D009928:Organ Specificity / Q000235:genetics
D000596:Amino Acids; D007527:Isoenzymes; D001224:Aspartic Acid; D002334:Carnitine O-Palmitoyltransferase; D003545:Cysteine