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Studies on the A Components of Drosophila Phenol Oxidase


Meltzer, Paul Stuart (1972) Studies on the A Components of Drosophila Phenol Oxidase. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/RYW9-R750.


In insects, the enzyme phenol oxidase is involved in the hardening and darkening of the cuticle. Drosophila phenol oxidase occurs in a latent form. Phenol oxidase activity is produced as a consequence of the interaction of several proteins. Three of these proteins are designated as the A components (A1, A2, A3). A quantitative assay for the A components has been developed. The A1 component has been prepared in stable and highly purified form by gel filtration, preparative electrofocusing, and preparative electrophoresis. No major contaminants could be detected by analytical polyacrylamide gel electrophoresis, analytical electrofocusing, SDS gel electrophoresis, and analytical ultracentrifugation. The A1 component has a molecular weight of approximately 77,000 daltons and an isoelectric point of 5.1. The isoelectric point of the A2 component is 6.0, and its molecular weight is similar to that of the A1 component. The A1 component has no detectable phenol oxidase activity and cannot be converted to active phenol oxidase by the S (salivary gland) component. The A1 component contains approximately 0.15% copper and does not contain large amounts of fatty acids or phosphate. The amino acid composition of A1 is reported. Microheterogeneity was observed in preparations of purified A1. The relationship of the A components to active phenol oxidase and the mechanism of the activation reaction are discussed.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:(Biochemistry and Developmental Biology)
Degree Grantor:California Institute of Technology
Major Option:Biochemistry
Minor Option:Developmental Biology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Mitchell, Herschel K.
Thesis Committee:
  • Unknown, Unknown
Defense Date:13 April 1972
Funding AgencyGrant Number
Record Number:CaltechTHESIS:06102016-143545592
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9870
Deposited On:13 Jun 2016 16:02
Last Modified:01 Jul 2024 22:44

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