Oscillatory Control of Glycolysis as a Model for
Biological Timing Processes
A. BETz
With 6 Figures
Abstract
Oscillatory control of glycolysis, the hitherto best known biochemical oscillator, is proposed as a model for biological timing systems. It works in yeast cells,
cell-free extracts of yeast cells and beef heart muscle and in rat liver mitochondria.
It affects not only glycolytic intermediates like sugar phosphates, pyridine and
adenine nucleotides, but also glucose incorporation in yeast and ion transport and
water binding in mitochondria. The glycolytic oscillator can be reset by adding
control chemicals. Its mechanism depends essentially on the control characteristics
of one or a few enzymes.
Biological Chronometry in Principle
Life itself is the realization of chemical processes in space and time. In
building up their characteristic structures, organisms undergo cycles of
growth, synthetic activit\', reproduction etc. Even in a completely constant
environment some kind of timing is necessary to coordinate all these
processes. There is a system controlling the correct sequence of reactions.
Cilia, for example, are effective in moving unicellular organisms as
well as in transport onh because they beat in a sequence ordered with
respect to space as well as time. Beating of heart muscle is a rhythmic
process, too, effective in transport. Its control depends on a timing system
which works on a cellular level, for even isolated cells persist in beating.
Peristaltic motion, another transport system, depends equally on welltimed muscle contraction.
Chronometry is even more important for organisms living under
regularly changing conditions of light intensity, temperature, humidity,
gravity etc. This is the case for most organisms because our earth is neither
air-conditioned nor a chemostat. Adaptation to changing conditions becomes more efficient when some regulatory processes can be initiated in
advance. It is advantageous for green algae to become mobile at sunrise and
to be ready for photosynthesis just as the sun is rising. Because of this advantage, it is not surprising that nearly all groups of animals and plants, ex-
Biological Timing Processes
A. BETz
With 6 Figures
Abstract
Oscillatory control of glycolysis, the hitherto best known biochemical oscillator, is proposed as a model for biological timing systems. It works in yeast cells,
cell-free extracts of yeast cells and beef heart muscle and in rat liver mitochondria.
It affects not only glycolytic intermediates like sugar phosphates, pyridine and
adenine nucleotides, but also glucose incorporation in yeast and ion transport and
water binding in mitochondria. The glycolytic oscillator can be reset by adding
control chemicals. Its mechanism depends essentially on the control characteristics
of one or a few enzymes.
Biological Chronometry in Principle
Life itself is the realization of chemical processes in space and time. In
building up their characteristic structures, organisms undergo cycles of
growth, synthetic activit\', reproduction etc. Even in a completely constant
environment some kind of timing is necessary to coordinate all these
processes. There is a system controlling the correct sequence of reactions.
Cilia, for example, are effective in moving unicellular organisms as
well as in transport onh because they beat in a sequence ordered with
respect to space as well as time. Beating of heart muscle is a rhythmic
process, too, effective in transport. Its control depends on a timing system
which works on a cellular level, for even isolated cells persist in beating.
Peristaltic motion, another transport system, depends equally on welltimed muscle contraction.
Chronometry is even more important for organisms living under
regularly changing conditions of light intensity, temperature, humidity,
gravity etc. This is the case for most organisms because our earth is neither
air-conditioned nor a chemostat. Adaptation to changing conditions becomes more efficient when some regulatory processes can be initiated in
advance. It is advantageous for green algae to become mobile at sunrise and
to be ready for photosynthesis just as the sun is rising. Because of this advantage, it is not surprising that nearly all groups of animals and plants, ex-