The Determination of Fumarase and Aconitase in Rat Liver Homogenate by Means of the Modified Racker’s Method

Abstract

A modification of Racker’s spectrophotometric method for the determination of fumarase (fumarate hydratase) and aconitase (aconitate hydratase) has been described. The described modification is more sensitive and more convenient than other methods. Beyond this, it may be used for the estimations in big series of samples. It also enables to obtain highest activities of both investigated enzymes at a suitable way of dilution, without the detergents. The inhibiting influence of DOC on fumarase but not on aconitase activity has been observed. Triton X-100 exerts no additional influence on the activity of both enzymes when compared with that of diluted samples without detergent.

Studies on the Latency of Rat Liver Fumarate Hydratase1

“…On the other hand, the ionic detergent DOC exerted a considerable inhibiting influence. Since the mitochondrial fumarase was determined according to the Racker's method modified in this laboratory [23] The activity of fumarase is almost completely inhibited by ionic detergents DOC, cholate and SDS at long and short incubation periods as well. Both the cytoplasmic enzyme and that localized in the mitochondrial matrix are being inhibited.…”

“…The fumarase activity was determined according to the spectrophotometric Racker's method modified in this laboratory [19,23]. L-malate prepared from L-malic acid (Koch-Light, England) was used as a substrate.…”

Submitochondrial localization of transferrin and iron accumulated by isolated rat liver mitochondria

“…(1) succinate dehydrogenase (EC 1.3.9.9) according to [19]; (2) monoamine oxidase (EC 1.4.3.4) by means of our modification of the spectrophotometric method [20]; (3) rotenone insensitive NADHcytochrome c reductase according to [21]; (4) aconitase (EC 4.2.1.3) by means of the modified method [22]. Assays for enzymic activities were performed in triplicate and the average values are given.…”

Investigation of Localization of Monoamine Oxidase (EC 1.4.3.4) in Subfraction of Rat Liver Mitochondria

“…Activities of the following mitochondrial enzymes were determined in the preparations of purified mitochondria and in the submitochondrial fractions: (1) monoamine oxidaseby means of our own modification [20] [19]. Assays for enzymic activities were performed in triplicate and the average values reported in all cases.…”