Halaseh A, Nigam S N, McConnell W B
Biochim Biophys Acta. 1977 Feb 28;496(2):272-7. doi: 10.1016/0304-4165(77)90309-9.
Metabolism of L-[35S]cystathionine, L-[35S]cysteine and L-[35S]homocysteine has been investigated in Astragalus pectinatus. The results indicate that cystathionine undergoes both beta and gamma cleavage to give homocysteine and cysteine. Results also show that cystathionine is synthesized from both cysteine and homocysteine. Furthermore, in addition to the incorporation of 35S into cystathionine, incorporation of 35S from cysteine into methionine and from homocysteine into S-methylcysteine is not only in agreement with the above cystathionine cleavage activities, but also suggests, that transsulfuration in A. pectinatus proceeds in both directions, eg. cysteine leads to cystathionine leads to homocysteine and homocysteine leads to cystathionine leads to cysteine. It is suggested, that the latter reaction may be contributing to the net synthesis of cysteine.
已对豆科植物地八角中L-[35S]胱硫醚、L-[35S]半胱氨酸和L-[35S]高半胱氨酸的代谢进行了研究。结果表明，胱硫醚会发生β-裂解和γ-裂解，生成高半胱氨酸和半胱氨酸。结果还表明，胱硫醚可由半胱氨酸和高半胱氨酸合成。此外，除了35S掺入胱硫醚外，半胱氨酸中的35S掺入蛋氨酸以及高半胱氨酸中的35S掺入S-甲基半胱氨酸，这不仅与上述胱硫醚裂解活性一致，还表明，地八角中的转硫作用是双向进行的，例如，半胱氨酸生成胱硫醚生成高半胱氨酸，高半胱氨酸生成胱硫醚生成半胱氨酸。有人认为，后一种反应可能有助于半胱氨酸的净合成。
