well to squib-firing mechanisms (where a capacitor is charged from a primary power source). The cells would make space vehicle subsystems less dependent on the main power supply. On the ground, the cells* main use may be to energize microelectronic circuits, since they can be directly incorporated into solid-state circuitry by standard techniques. Also for the future, the JPL workers have made a cell completely from synthetic materials containing only carbon, hydrogen, and nitrogen. The cell developed 0.15 volt with only a minute current.
Luciferase has active SH groups A decapeptide containing a reactive sulfhydryl group (SH) has been isolated and identified from the firefly enzyme luciferase by Dr. W. D. McElroy and Dr. James Travis at Johns Hopkins University, Baltimore, Md. [Biochemistry, 5, 2170 (1966)]. Luciferase, when coupled to luciferyl adenylate (luciferin and adenosine triphosphate), gives rise to the light emitted by fireflies. Dr. McElroy and Dr. Travis have found that luciferase is composed of two identical monomers, each containing a sulfhydryl group. The two sulfhydryl groups are intimately involved in the action of the enzyme. This information, along with molecular weight studies, led the Johns Hopkins workers to a better understanding of the structure and function of the enzyme. They determined the molecular weights of luciferase by two sedimentation methods—low-speed and highspeed equilibrium techniques. Lowspeed equilibrium studies performed at 4° C. in 10% ammonium sulfate at pH 7.8 gave values of 89,000 to 91,000 for the molecular weight of luciferase. The high-speed centrifugations in 0.1M tris buffer and at p H 7.0 gave molecular weight values of 92,000 to 95,000. In 5M guanidine hydrochloride, the enzyme dissociates into two subunits, each having a molecular weight of 52,000. In dehydroluciferyl adenylate, titrations of luciferase with 5,5 r -dithiobis (2-nitrobenzoic acid) resulted in the reaction of four of the six sulfhydryl groups in the enzyme. This indicates that two sulfhydryl groups are tied up by dehydroluciferyl adenylate. A decapeptide containing the reactive sulfhydryl group was isolated from the tryptic digests of luciferase. The original luciferase was alkylated with [l- 14 C]IV-ethylmaleimide (NEM). The NEM peptide was the only radioactive peptide isolated by the Johns Hopkins workers from the tryptic di-
gestion, which was carried out in 0.1 M triethylamine buffer of pH 8.1. The decapeptide contains cysteine, aspartic acid, serine, glutamic acid, glycine, alanine, and lysine. To determine the sequence of amino acids, the decapeptide was subjected to five successive Edman degradations. In these degradations, the IV-terminal amino acids are broken away (with phenylisothiocyanate) from the peptide as N-phenylthiohydantoins. Other degradations were carried out on the decapeptide with subtilisin and carboxypeptidase A. Carboxypeptidase A split off no amino acids. However, Dr. McElroy separated four components by high-voltage electrophoresis from the subtilisin digestion of the peptide. These components were identified by Edman degradations. The sequence of amino acids in the decapeptide is serine, cysteine, glutamic acid, glysine, asparagine, alanine, glycine, serine, glutamine, and lysine.
Pathologists sued for antitrust "Foul!" cried the College of American Pathologists when the Justice Department brought suit against the Chicagobased group on antitrust charges. The suit, among other things, charges that the pathologists conspired to operate all clinical laboratories and to force out of business laboratories operated by others, such as chemists and biologists. Coming hard on the heels of the start of the medicare program, the suit apparently struck a nerve: "The timing of this action, coming as it does at the inception of medicare and immediately following the American Medical Association annual meeting, makes it appear that this is but the first step in a campaign of harassment of the entire medical profession by the Government," said Dr. Oliver J. Neibel, executive director of the college, in a statement. According to the Justice Department, almost all of the nation's 20,000 clinical laboratories are run by members of the association. Total business of these labs amounts to more than $3 billion annually. In the suit, Justice charges that the association and its members, among other things, conspired to: •Fix prices at artificially high levels for laboratory services. • Have all doctors boycott "all commercial medical laboratories not owned and operated solely for the profit of pathologists/* • Have doctors refuse salaried positions with any profit-making hospital unless the entire profit from its medical laboratory goes to a pathologist. As a result of these actions, Justice
Pathologists' Neibel A campaign of harassment
says, the public has been forced to pay higher prices for clinical laboratory services, doctors are prevented from dealing with the laboratories of their choice, and laboratories not operated solely for the profit of pathologists are prevented from expanding their markets free of unreasonable restraints on competition. The department asks the U.S. District Court (Northern District of Illinois) for an injunction against further alleged monopolistic practices by the college. It also wants the court to issue an order requiring whatever action is necessary to restore competition to the commercial medical laboratory industry in this country. Dr. Neibel says, "Some months ago we received a civil investigative demand from the Department of Justice which requested that we produce a number of documents relating to the internal affairs of our scientific organization . . . . We literally opened our files to the department. We have heard nothing further from the department since that time. "Thus, the college is surprised and shocked at the serious action brought against it . . . . Our members, as part of the medical profession, are not engaged in commercial business," he adds. "Our members throughout the country," Dr. Neibel says, "are now at home doing their utmost to cooperate with the Government in implementing the substantial additional burdens placed on all physicians by the new medicare law. Although the college has cooperated fully with the Government, the Government has requested no advance conference to attempt to point out where it thought the college might be violating the law." JULY 18, 1966 C&EN
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