| Autor: |
Schreiner CL; Department of Biochemistry, North Carolina State University, Raleigh 27695., Jones EE |
| Jazyk: |
angličtina |
| Zdroj: |
The Journal of nutrition [J Nutr] 1988 Jul; Vol. 118 (7), pp. 818-28. |
| DOI: |
10.1093/jn/118.7.818 |
| Abstrakt: |
In previous studies we have found that porcine kidney fibroblasts will grow in medium containing D-2-hydroxy-4-methylthiobutanoic acid (D-methionine hydroxy analogue, D-MHA) as the sole source of methionine but not in medium containing the L-isomer (L-MHA) alone. The fibroblasts have been found to have both D-2-hydroxy acid dehydrogenase (EC 1.1.99.6), which uses D-MHA as substrate (Km = 6.0 mM) and L-2-hydroxy acid oxidase (EC 1.1.3.1), which uses L-MHA as substrate (Km = 7.1 mM). These two activities should make it possible for the fibroblasts to grow on either isomer. Only one protein band with L-2-hydroxy acid oxidase activity can be detected with enzyme-specific staining of protein profiles obtained after polyacrylamide gel electrophoresis. The enzyme L-2-hydroxy acid oxidase from porcine kidney has properties that are different from the two porcine isozymes reported previously by others. Passage of DL-[14C]MHA at tracer levels into the porcine kidney fibroblasts in culture is reduced to 31% of control in the presence of 3.75 mM D-MHA, 86% of control with 3.75 mM L-MHA and 65% with 3.75 mM D-lactate but is not affected by up to 3.75 mM L-lactate. It appears that the transport specificity is the basis for the growth promotion of kidney fibroblasts by the D-isomer of MHA as opposed to L-MHA when each is used as the sole source of methionine. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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