Hand A R
J Histochem Cytochem. 1976 Aug;24(8):915-25. doi: 10.1177/24.8.956644.
The ultrastructural localization of catalase and L-alpha-hydroxy acid oxidase (LalphaHAO) was studied in two species of Hydra. Diaminobenzidine reaction product of catalase activity was present in small round or elongated bodies resembling microperoxisomes in the epitheliomuscular, digestive and gland cells. They were closely related to the endoplasmic reticulum, and were often found in proximity to deposits of lipid and glycogen. Reaction product of LalphaHAO activity was also associated with the microperoxisomes. With rapidly oxidized substrates, such as L-lactic acid, reaction product diffused into the cytoplasm around the microperoxisomes. With slowly oxidized substrates, such as DL-alpha-hydroxyisovaleric acid, reaction product was restricted to the matrix of the microperoxisomes. No reaction product was present in the microperoxisomes in the absence of substrate or with D-lactic acid. The rate of substrate oxidation measured biochemically roughly paralleled the amount of cytochemical reaction product deposited with different substrates. Microperoxisome-like bodies reactive for LalphaHAO were also found in the epidermal cnidoblasts; however, catalase could not be demonstrated in them. This study provides the first cytochemical evidence for the presence of an H2O2-producing oxidase in microperoxisomes.
在两种水螅中研究了过氧化氢酶和L-α-羟酸氧化酶（LalphaHAO）的超微结构定位。过氧化氢酶活性的二氨基联苯胺反应产物存在于上皮肌细胞、消化细胞和腺细胞中类似微过氧化物酶体的小圆形或细长形小体中。它们与内质网密切相关，并且经常在脂质和糖原沉积物附近发现。LalphaHAO活性的反应产物也与微过氧化物酶体相关。对于快速氧化的底物，如L-乳酸，反应产物扩散到微过氧化物酶体周围的细胞质中。对于缓慢氧化的底物，如DL-α-羟基异戊酸，反应产物局限于微过氧化物酶体的基质中。在没有底物或使用D-乳酸的情况下，微过氧化物酶体中不存在反应产物。通过生化方法测量的底物氧化速率大致与用不同底物沉积的细胞化学反应产物的量平行。在表皮刺细胞中也发现了对LalphaHAO有反应的微过氧化物酶体样小体；然而，在其中未证实有过氧化氢酶。这项研究为微过氧化物酶体中存在产生H2O2的氧化酶提供了首个细胞化学证据。
