11.5 Enzyme Inhibitors Produced by Marine Microorganisms
11.5.1 Protease Inhibitors
Various enzymes must perform roles within the body for the organism to survive.
When those activities are too strong or too weak, the homeostasis that maintains the
body in a certain state cannot be sustained.
Enzyme inhibitors are substances that bind with enzymes and block their
activities. They play an important role in maintaining enzyme activity at normal
levels.
Protease inhibitors are among the most widely studied enzyme inhibitors, with a
broad range of applications in the treatment of various diseases caused by irregular
protease activity.
These enzyme inhibitors are important not only in the analysis of enzyme
reaction mechanisms, but also in the fields of medicine, pharmacology, and agricultural and fishery science. Accordingly, they have been the subject of a great deal
of exploratory research to date, principally in land-based organisms.
The protease inhibitors isolated to date can be broadly divided into polymers
such as proteins and low-molecular weight organic compounds. The former are
found principally in plants and animals, while the latter have been derived from
actinomycetes and other land-based micoorganisms, but rarely from marine
microorganisms.
Recent years have seen growing attention to the isolation and characteristics of
new enzyme inhibitors from marine microorganisms, with potential future applications in the fields of medicine, pharmacology, and agricultural and fishery science
(Paterson et al. 2000; Imada 2009).
A. The Searching Process for Protease Inhibitor-Producing Bacteria
A marine microorganism’s ability to produce metabolites such as antibiotics or
enzyme inhibitors is known to vary drastically with culturing conditions. This
requires changes in seawater concentrations, salt concentrations, pH, carbon and
nitrogen sources, culturing time, and other conditions to find the optimal conditions
for inhibitor production.
To locate protease inhibitor-producing bacteria, marine bacteria are inoculated
into a seawater medium with added casein and cultured for several days at 27 °C
while protease solution is sprinkled on the medium surface. When left for several
hours, the casein proteins are broken down by the action of the protease, causing the
medium to become transparent. In the area around the inhibitor-producing bacteria
colony, the protease activity is diminished by the inhibitor that has been produced,
leaving an opaque halo of undegraded casein. This provides an easy means of
distinguishing bacteria that do and do not produce inhibitors (Fig. 11.7; the
inhibitor-producing bacteria are at the center).
This method can be used to easily identify protease inhibitor-producing marine
bacteria.
11.5 Enzyme Inhibitors Produced by Marine Microorganisms
405
11.5.1 Protease Inhibitors
Various enzymes must perform roles within the body for the organism to survive.
When those activities are too strong or too weak, the homeostasis that maintains the
body in a certain state cannot be sustained.
Enzyme inhibitors are substances that bind with enzymes and block their
activities. They play an important role in maintaining enzyme activity at normal
levels.
Protease inhibitors are among the most widely studied enzyme inhibitors, with a
broad range of applications in the treatment of various diseases caused by irregular
protease activity.
These enzyme inhibitors are important not only in the analysis of enzyme
reaction mechanisms, but also in the fields of medicine, pharmacology, and agricultural and fishery science. Accordingly, they have been the subject of a great deal
of exploratory research to date, principally in land-based organisms.
The protease inhibitors isolated to date can be broadly divided into polymers
such as proteins and low-molecular weight organic compounds. The former are
found principally in plants and animals, while the latter have been derived from
actinomycetes and other land-based micoorganisms, but rarely from marine
microorganisms.
Recent years have seen growing attention to the isolation and characteristics of
new enzyme inhibitors from marine microorganisms, with potential future applications in the fields of medicine, pharmacology, and agricultural and fishery science
(Paterson et al. 2000; Imada 2009).
A. The Searching Process for Protease Inhibitor-Producing Bacteria
A marine microorganism’s ability to produce metabolites such as antibiotics or
enzyme inhibitors is known to vary drastically with culturing conditions. This
requires changes in seawater concentrations, salt concentrations, pH, carbon and
nitrogen sources, culturing time, and other conditions to find the optimal conditions
for inhibitor production.
To locate protease inhibitor-producing bacteria, marine bacteria are inoculated
into a seawater medium with added casein and cultured for several days at 27 °C
while protease solution is sprinkled on the medium surface. When left for several
hours, the casein proteins are broken down by the action of the protease, causing the
medium to become transparent. In the area around the inhibitor-producing bacteria
colony, the protease activity is diminished by the inhibitor that has been produced,
leaving an opaque halo of undegraded casein. This provides an easy means of
distinguishing bacteria that do and do not produce inhibitors (Fig. 11.7; the
inhibitor-producing bacteria are at the center).
This method can be used to easily identify protease inhibitor-producing marine
bacteria.
11.5 Enzyme Inhibitors Produced by Marine Microorganisms
405