Related Experiment Video

Updated: Aug 17, 2026

Analysis of the Mitochondrial Density and Longitudinal Distribution in Rat Live-Skeletal Muscle Fibers by Confocal Microscopy
10:53

Analysis of the Mitochondrial Density and Longitudinal Distribution in Rat Live-Skeletal Muscle Fibers by Confocal Microscopy

Published on: December 1, 2023

[Evidence for existence of type A MAO in mitochondria from human placenta (author's transl)]

R Kikuchi, H Kinemuchi

    Nihon Yakurigaku Zasshi. Folia Pharmacologica Japonica
    |September 1, 1978
    PubMed

    Insights

    Human placenta mitochondria contain primarily one type of monoamine oxidase (MAO), which functions similarly to type A MAO found in other species. This finding clarifies MAO

    Area of Science:

    • Biochemistry
    • Enzymology
    • Mitochondrial research

    Background:

    • Monoamine oxidase (MAO) exists in two main forms, type A and type B, with distinct substrate specificities and inhibitor sensitivities.
    • Understanding MAO distribution and characteristics in human tissues, such as the placenta, is crucial for comprehending its physiological roles.

    Purpose of the Study:

    • To investigate the presence and characteristics of type A and B MAO in human placenta mitochondria.
    • To compare the properties of placental MAO with those found in rat liver mitochondria.

    Main Methods:

    • Enzyme inhibition assays using selective MAO inhibitors (clorgyline, pargyline, deprenyl) and specific substrates (serotonin, tyramine, beta-phenylethylamine).
    • Comparison of substrate oxidation rates and enzyme sensitivity to tryptic digestion with rat liver MAO.
    • Sucrose density gradient centrifugation to assess MAO fractions.

    Main Results:

    • Human placental MAO exhibited significantly different substrate oxidation rates compared to rat liver MAO.
    • Placental MAO was more susceptible to tryptic digestion than rat liver MAO.
    • Inhibitor sensitivity and substrate specificity experiments indicated that placental MAO predominantly resembles type A MAO.

    Conclusions:

    • Mitochondria in human placenta primarily contain a single distinguishable type of MAO.
    • This identified MAO type closely aligns with the characteristics of type A MAO observed in other mammalian tissues.

    More Related Videos

    Isolation of Mitochondria for Mitochondrial Supercomplex Analysis from Small Tissue and Cell Culture Samples05:45

    Isolation of Mitochondria for Mitochondrial Supercomplex Analysis from Small Tissue and Cell Culture Samples

    Published on: May 3, 2024

    High-Resolution Fluorespirometry to Assess Dynamic Changes in Mitochondrial Membrane Potential in Human Immune Cells07:18

    High-Resolution Fluorespirometry to Assess Dynamic Changes in Mitochondrial Membrane Potential in Human Immune Cells

    Published on: May 24, 2024

    Related Concept Videos

    Animal Mitochondrial Genetics02:59

    Animal Mitochondrial Genetics

    Among all the organelles in an animal cell, only mitochondria have their own independent genomes. Animal mitochondrial DNA is a double-stranded, closed-circular molecule with around 20,000 base pairs. Mitochondrial DNA is unique in that one of its two strands, the heavy, or H, -strand is guanine rich, whereas the complementary strand is cytosine rich and called the light, or L, -strand. Compared to nuclear DNA, mitochondrial DNA has a very low percentage of non-coding regions and is marked by...
    Mitochondrial Membranes01:45

    Mitochondrial Membranes

    A single mitochondrion is a bean-shaped organelle enclosed by a double-membrane system. The outer membrane of mitochondria is smooth and contains many porins - the integral membrane transporters. Porins enable free diffusion of ions and small uncharged molecules through the outer mitochondrial membrane but limit the transport of molecules larger than 5000 Daltons. Further, the outer mitochondrial membrane forms a unique structure called membrane contact sites with other subcellular organelles,...
    The Inner Mitochondrial Membrane01:28

    The Inner Mitochondrial Membrane

    The inner mitochondrial membrane is the primary site of ATP synthesis. The inner membrane domain that forms a smooth layer adjacent to the outer membrane is called the inner boundary membrane. This domain contains membrane transporters that drive metabolites in and out of the mitochondria.  In contrast, the inner membrane network that invaginates into the matrix space is called the cristae membrane. This domain accounts for principle mitochondrial function as it accommodates the protein...
    Mitochondrial Precursor Proteins01:39

    Mitochondrial Precursor Proteins

    Mitochondrial precursors are partially unfolded or loosely folded polypeptide chains. Newly synthesized precursors are inhibited from spontaneously folding into their native conformation by the cytosolic chaperones, heat shock proteins 70 (Hsp70), and mitochondrial import stimulation factors (MSFs). Precursors bound to MSFs are guided to the TOM70-TOM37 receptors, while precursors bound to Hsp70  chaperones are targetted to TOM20-TOM22 receptor complexes.
    Most of the mitochondrial precursors...
    Translocation of Proteins into the Mitochondria01:19

    Translocation of Proteins into the Mitochondria

    Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
    Sorting of outer membrane proteins:
    Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
    Porin Insertion in the Outer Mitochondrial Membrane01:12

    Porin Insertion in the Outer Mitochondrial Membrane

    Porins are beta-barrel proteins translocated to the mitochondrial outer membrane through the TOM complex into the intermembrane space. Porin precursors bind TIM chaperones within the intermembrane space and are guided to the Sorting and Assembly Machinery complex or SAM complex on the outer mitochondrial membrane.
    Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...