Department of Biology, Reed College, Portland, Oregon 97202.
Plant Physiol. 1979 Aug;64(2):176-81. doi: 10.1104/pp.64.2.176.
The incorporation of dl-[(14)C]phenylalanine into phenylacetate reported previously in leaf enzyme preparations has been found to be catalyzed by two separate enzyme activities leading to phenylpyruvate, one using the l-, the other the d-isomer. Since both reactions occur anaerobically and are increased by the addition of pyridoxal phosphate and alpha-ketoglutarate, two transaminase (aminotransferase) activities appear to be involved. The activities of the l- and d-dependent forms are approximately equal in a crude particulate fraction, but range from 1:1 to 3:1 in a soluble supernatant fraction. Nonisotopic as well as isotopic assays to separate d- and l-activities are described.
先前在叶片酶制剂中报道的 dl-[(14)C]苯丙氨酸掺入苯乙酸的反应,现已发现是由两种单独的酶活性催化的,分别导致苯丙酮酸,一种使用 l-异构体,另一种使用 d-异构体。由于这两种反应都是在无氧条件下发生的,并且添加吡哆醛磷酸盐和α-酮戊二酸会增加反应,因此似乎涉及两种转氨酶(氨基转移酶)活性。在粗颗粒部分中,l-和 d-依赖性形式的活性大致相等,但在可溶性上清液部分中,活性范围为 1:1 至 3:1。本文描述了分离 d-和 l-活性的非同位素和同位素测定方法。