TY - JOUR
T1 - Identification of the enzymatic lesions responsible for the accumulation of acetylated sphingosine bases in the yeast Hansenula ciferri
AU - Barenholz, Yechezkel
AU - Gadot, Nathan
AU - Valk, Eliyahu
AU - Gatt, Shimon
PY - 1973/5/24
Y1 - 1973/5/24
N2 - The enzymatic lesions responsible for the accumulation of acetylated sphingosine bases in the "high producer" strains of the genus Hansenula were studied. Two strains, one a "low" and the other a "high" producer, were selected to compare four enzymatic steps leading to the synthesis of acetylated dihydrosphingosine by yeast microsomes. Both strains were very similar in their generation time and DNA content, but the high producer accumulated 150 times more sphingosine bases than the low producer. Among the four microsomal enzymes, the specific activity of the palmityl thiokinase and 3-ketodihydrosphingosine reductase were almost identical in the two strains. In contrast, the specific activity of the 3-ketodihydrosphingosine synthetase, which catalyzed the rate-limiting step in dihydrosphingosine biosynthesis, was 5-10-fold greater in the high producer strain than in the low producer. The long-chain base-acetyl-CoA acetyltransferase was at least 30 times more active in the high as compared with the low producer. It therefore seems that the latter two enzymes may be the cause for the in vivo accumulation of acetylated sphingosine bases in the high producers.
AB - The enzymatic lesions responsible for the accumulation of acetylated sphingosine bases in the "high producer" strains of the genus Hansenula were studied. Two strains, one a "low" and the other a "high" producer, were selected to compare four enzymatic steps leading to the synthesis of acetylated dihydrosphingosine by yeast microsomes. Both strains were very similar in their generation time and DNA content, but the high producer accumulated 150 times more sphingosine bases than the low producer. Among the four microsomal enzymes, the specific activity of the palmityl thiokinase and 3-ketodihydrosphingosine reductase were almost identical in the two strains. In contrast, the specific activity of the 3-ketodihydrosphingosine synthetase, which catalyzed the rate-limiting step in dihydrosphingosine biosynthesis, was 5-10-fold greater in the high producer strain than in the low producer. The long-chain base-acetyl-CoA acetyltransferase was at least 30 times more active in the high as compared with the low producer. It therefore seems that the latter two enzymes may be the cause for the in vivo accumulation of acetylated sphingosine bases in the high producers.
UR - http://www.scopus.com/inward/record.url?scp=0015934666&partnerID=8YFLogxK
U2 - 10.1016/0005-2760(73)90239-7
DO - 10.1016/0005-2760(73)90239-7
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C2 - 4713160
AN - SCOPUS:0015934666
SN - 0005-2760
VL - 306
SP - 341
EP - 345
JO - Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
JF - Biochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
IS - 2
ER -