Variations in Sulfhydryl Concentration During Microsporocyte Meiosis in the Anthers of Lilium and Trillium

The accumulation of soluble deoxyribosidic compounds in relation to nuclear division in anthers of Lilium longiflorum

Intervals of sporogenous DNA synthesis in lily anthers are associated with marked accumulations of methanol- and acid-soluble deoxyribosidic compounds. There are differences in solubility between compounds accumulating at meiosis and those accumulating at mitosis. The formation of these compounds appears to be related to a breakdown of somatic DNA.

Studies on sulfhydryl groups during cell division of sea urchin egg. III. SH groups of KC1-soluble proteins and their change during cleavage

Sea urchin egg proteins extracted with KCl are mostly TCA-soluble and, conversely, those extracted with TCA are KCl-soluble. Both groups are water-insoluble and show fluctuations in—SH content during the division cycle. The fluctuation of the—SH groups of the KCl-soluble protein of the whole egg is due to a —SH⇌—S—S— interchange within the freely reacting groups and not within the sluggish and masked —SH groups of the protein. The —SH content of the KCl-soluble protein of the egg cortex also fluctuates in a similar way.

Identification of mitosis-specific p65 dimer as a component of human M phase-promoting factor

Antisera raised against two mitosis-specific protein kinases from human cells recognized a single 65-kDa polypeptide (p65) that is present in similar amounts in interphase and mitotic cell extracts. Immunoblot analysis of reduced and unreduced extracts revealed that p65 exists as a 65-kDa monomer during interphase but forms a 130-kDa disulfide-linked homodimer during mitosis. Several different antibodies recognizing the p34cdc2 protein kinase and cyclin B components of M phase-promoting factor (MPF) coprecipitated p65 from mitotic but not from interphase extracts. In addition, an anti-p65 immunoaffinity column substantially depleted mitotic extracts of histon H1 kinase activity assayed under conditions diagnostic for MPF. These results suggest that active human MPF may be a complex of p34cdc2, cyclin B, and dimeric p65. A sulfhydryl cycle, proposed in the earlier literature on the biochemistry of mitosis, might underlie the dimerization of p65 and formation of active MPF.

Sulphane sulphur in biological systems: a possible regulatory role

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