GHIRETTI F, GHIRETTI-MAGALDI A, TOSI L
J Gen Physiol. 1959 Jul 20;42(6):1185-205. doi: 10.1085/jgp.42.6.1185.
The classic spectrophotometric method for identification and characterization of respiratory enzymes has been used for the study of the cytochrome system of Aplysia. Particles have been prepared from the buccal mass and the gizzard muscles. Difference spectra taken on isolated particle suspensions show the presence of a complete cytochrome system composed of five components: cytochrome a, b, c, c(1), and a(3). As indicated by the peaks of the sharp absorption bands of their reduced forms, they are very similar to the cytochromes of mammals and yeast. Cytochrome a(3) has been identified as the terminal oxidase of Aplysia muscle by means of the spectrophotometric study of its carbon monoxide compound. Further evidence for the presence of a cytochrome system in Aplysia was obtained by assays of the catalytic activities of the isolated particles: succinic dehydrogenase, cytochrome oxidase, DPNH cytochrome c reductase. The cytochrome oxidase activity was strongly inhibited by carbon monoxide in the dark; the inhibition was totally relieved by light. Cytochrome c has been extracted and purified from muscle tissue. Its spectrum is almost identical with that of the mammalian pigment both in the oxidized and reduced forms. From the hepatopancreas a new respiratory enzyme has been extracted which has many physical and chemical properties in common with cytochrome h from terrestrial snails.
用于鉴定和表征呼吸酶的经典分光光度法已被用于研究海兔的细胞色素系统。已从口球和砂囊肌肉制备了颗粒。对分离的颗粒悬浮液进行的差光谱显示存在由五个成分组成的完整细胞色素系统：细胞色素a、b、c、c(1)和a(3)。从其还原形式的尖锐吸收带的峰值可以看出，它们与哺乳动物和酵母的细胞色素非常相似。通过对其一氧化碳化合物的分光光度研究，细胞色素a(3)已被鉴定为海兔肌肉的末端氧化酶。通过对分离颗粒的催化活性进行测定，获得了海兔中存在细胞色素系统的进一步证据：琥珀酸脱氢酶、细胞色素氧化酶、DPNH细胞色素c还原酶。在黑暗中，一氧化碳强烈抑制细胞色素氧化酶的活性；光照可完全解除这种抑制。细胞色素c已从肌肉组织中提取并纯化。其光谱在氧化和还原形式下几乎与哺乳动物色素的光谱相同。已从肝胰腺中提取出一种新的呼吸酶，它在许多物理和化学性质上与陆生蜗牛的细胞色素h相同。
