The degradation of the major seed storage globulins of the soybean (Glycine max [L.] Merrill) was examined during the first 12 days of germination and seedling growth. The appearance of glycinin and flconglycinin degradation products was detected by sodium dodecyl sulfatepolyacrylamide gel electrophoresis of cotyledon extracts followed by electroblotting to nitrocellulose and immunostaining using glycinin and B-conglycinin specific antibodies. The three subunits of fl-conglycinin were preferentially metabolized. Of the three subunits of j-conglycinin, the larger a and a' subunits are rapidly degraded, generating new #-conglycinin cross-reactive polypeptides of 51,200 molecular weight soon after imbibition of the seed. After 6 days of growth the a-subunit is also hydrolyzed. At least six polypeptides, ranging from 33,100 to 24,000 molecular weight, appear as apparent degradation products of f-conglycinin. The metabolism of the glycinin acidic chains begins early in growth. The glycinin acidic chains present at day 3 have already been altered from the native form in the ungerminated seed, as evidenced by their higher mobility in an alkaline-urea polyacrylamide gel electrophoresis system. However, no change in the molecular weight of these chains is detectable by sodium dodecyl sulfate-polyarylamide gel electrophoresis. Examination of the glycinin polypeptide amino-termini by dansylation suggests that this initial modification of the acidic chains involves limited proteolysis at the carboxyl-termini, deamidation, or both. After 3 days of growth the acidic chains are rapidly hydrolyzed to a smaller (21,900 molecular weight) form. The basic polypeptides of glycinin appear to be unaltered during the first 8 days of growth, but are rapidly degraded thereafter to unidentified products. All of the original glycinin basic chains have been destroyed by day 10 of growth.During the development ofthe dicot seed on the mother plant, storage molecules, particularly starches, proteins, and triglycerides, are laid down in the seed. These reserves are mobilized during germination and seedling growth to supply the energy and metabolic intermediates needed by the seedling prior to the establishment of photosynthetic autotrophism. In the legume seed a relatively large fraction of these reserves, on a weight basis, is composed of storage proteins.The major legume storage proteins are the globulins legumin and vicilin. In the soybean (Glycine max [L.] Merrill) these proteins are called glycinin and fl-conglycinin, respectively.Much work has been done on the structure, biosynthesis, and genetics of these soybean proteins (15,18,20), as well as on their degradation by mammalian trypsin (10-12). However, essen-'Supported by National Science Foundation grant PCM 8301202. A preliminary account of this investigation has been published as Ref. 29. 71 tially no work has been done on their degradation in vivo during germination and seedling growth. We have previously demonstrated that the Bowman-Birk and Kunitz trypsin inhibitor...

The amino acid sequence of the major trypsin inhibitor, F, of ungerminated mung beans (Vigna radiata IL.I Wilczek) was determined by a combination of automatic solid phase and manual sequencing techniques. F is a typical Bowman-Birk-type proteinase inhibitor with 80 amino acid residues and exhibits a high degree of identity with the other sequenced members of the Bowman-Birk family of inhibitors. Thin layer peptide maps of mung bean inhibitors E and C (which appear during germination) indicate that both are derived from inhibitor F by limited specific proteolysis. Loss of the carboxyl-terminal residues 77 to 80 from F produces inhibitor E, while the loss of an additional two carboxyl-terminal residues, the loss of the amino-terminal residues I to 8, and an internal cleavage at

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tive saturation. The generally accepted scheme for transition metal systems (eq 14) requires an empty co-CHi=CHR I MCH2CH2R =5=^MH ->• MH + CH2==CHR (14) E ordination position, which is sometimes created by dissociation of another ligand.92•93 Attempts in this laboratory to prepare (C5H6)3UH have so far been unsuccessful.Additional Reactions. Over a period of several hours there was no evidence from pmr spectra that (C6H5)3UR compounds added to either acetone or C02 to produce the corresponding alkoxide25 or carboxylate.94 Thus, these uranium alkyls, though susceptible (92) (a) C. A. Tolman, Chem. Soc. Rev., 1, 337 (1972). (b) That the trihaptoa\\y\ configuration could be as much as 8-9 kcal/mol above the monohapto configuration in (CsHalsUlCaHs) supports this, though the steric requirements of E may be somewhat different.(93) Thermal decomposition of the reaction product of UCL + 4n-C4H»Li in diethyl ether or hexane yields butene and butane, but only traces of octane. These products appear to arise via ß elimination: T. J. Marks and A. M. Seyam, submitted for publication.

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