Abstract: A process for converting AMP into ATP which comprises (a) using an enzyme which converts AMP into ADP and has been produced from microorganisms having an optimum growth temperature of 50.degree. C. to 85.degree. C. and an enzyme which converts ADP into ATP and has been produced from microorganisms having an optimum growth temperature of 50.degree. C. to 85.degree. C. is disclosed. In addition, there is disclosed a process for producing a physiologically active substance by a multienzyme process which comprises forming ATP from AMP by the step (a), (b) synthesizing a physiologically active substance with the resulting ATP, converting AMP resulting from the reaction in step (b) into ATP by the reaction in step (a), and repeatedly utilizing the converted ATP for synthesis of the physiologically active substance in step (b). By using the process it is possible to stably and efficiently carry out conversion of AMP into ATP over a long period of time.

Abstract: A process for converting AMP into ATP which comprises (a) using an enzyme which converts AMP into ADP and has been produced from microorganisms having an optimum growth temperature of 50.degree. C. to 85.degree. C. and an enzyme which converts ADP into ATP and has been produced from microorganisms having an optimum growth temperature of 50.degree. to 85.degree. C. is disclosed. In addition, there is disclosed a process for producing a physiologically active substance by a multienzyme process which comprises forming ATP from AMP by the step (a), (b) synthesizing a physiologically active substance with the resulting ATP, coverting AMP resulting from the reaction in step (b) into ATP by the reaction in step (a), and repeatedly utilizing the converted ATP for synthesis of the physiologically active substance in step (b). By using the process it is possible to stably and efficiently carry out conversion of AMP into ATP over a long period of time.

Abstract: A heat-resistant adenylate kinase is described whose activity after an incubation in a buffer solution at about 50.degree. C. for about 15 minutes is at least about 80% of the original activity prior to the incubation. This adenylate kinase can be obtained by cultivating a bacterium belonging to the genus Bacillus and collecting adenylate kinase from the resulting culture broth. This heat-resistant enzyme is very stable against heat and, therefore, after isolation, it can be stored for a long period of time compared with the conventional adenylate kinase.

Abstract: A process for synthesizing peptides or peptide derivatives is disclosed. The process involves using aminoacyl-tRNA synthetase as a condensing agent when synthesizing peptides or peptide derivatives from amino acids. According to the process, peptides or peptide derivatives which are useful as various hormones such as bradykinin having antihypertensive activity or somatostatin having an internal or external secretion controlling function and other biologically active substances such as antibiotic peptides or seasoning peptides can be produced at a moderate price without using protective groups.

Abstract: An apparatus for converting into ATP which comprises an enzyme reactor, a source of AMP supply, a source of phosphoric acid donator supply, variable fluid sending apparatus, an automatic sampling apparatus and an analyzing apparatus for the reacting solution, an arithmetic control apparatus, and a recovery apparatus. According to this apparatus, conversion from AMP or ADP into ATP can be effectively carried out and ATP conversion can be kept at substantial 100% over a long period of time. The device makes it possible for ATP to be used more and more in future as an energy source for bioreactors and as medicines because the ATP will be more readily available and less expensive.