The molecular biology and biochemistry of rice endosperm. alpha. -globulin

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5672224

Shorrosh, B S

The author's first objective was to isolate a cDNA clone that encodes the rice endosperm {alpha}-globulin. Purified antibodies against a rice storage protein, {alpha}-globulin, were used to screen a {lambda}gt11 cDNA expression library constructed from immature rice seed endosperm. The cDNA insert of clone 4A1 (identified by antibody screening) was used as a probe to identify long cDNA inserts in the library. The deduced amino acid sequence of clone A3-12 cDNA insert (identified by cDNA screening) contained the amino acid sequences of three cyanogen bromide peptides fragment of {alpha}-globulin. The calculated molecular weight and amino acid composition of the deduced amino acid sequence were similar to the {alpha}-globulin protein. Northern blot analysis indicated that mRNA of one size, approximately 1.0 kb, is expressed. Southern genomic blot analysis revealed one band with EcoRI or Hind III digestion. Cell-free translation and immunoprecipitation showed that the initial translation product is approximately 2,000 daltons larger than the mature protein. The amino acid sequence of {alpha}-globulin revealed limited regions of similarities with wheat storage proteins. The author concludes that the cDNA insert in clone A3-12 contained the entire coding region of {alpha}-globulin protein and that {alpha}-globulin is encoded by a single gene. My second objective was to inhibit the degradation of {alpha}-globulin in the salt extract of rice flour. The salt extract of rice flour contained an acid protease whose optimal pH was 3 for {sup 3}H-casein hydrolysis. A polypeptide with molecular weight of 20,000 was immunologically reactive with {alpha}-globulin antibodies and is produced by limited proteolysis in the extract. Pepstatin inhibited the proteolysis of 3H-casein and slowed the proteolysis of {alpha}-globulin.

• Research Organization: Kansas State Univ., Manhattan, KS (USA)
• OSTI ID: 5672224
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
550501 -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINO ACID SEQUENCE
BIOASSAY
BIOCHEMISTRY
CASEIN
CEREALS
CHEMISTRY
DNA
GENES
GLOBULINS
GRAMINEAE
HYDROGEN COMPOUNDS
IMMUNOASSAY
ISOTOPE APPLICATIONS
LILIOPSIDA
MAGNOLIOPHYTA
MESSENGER-RNA
METABOLISM
MOLECULAR BIOLOGY
MOLECULAR STRUCTURE
MOLECULAR WEIGHT
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
PLANTS
PROTEINS
RICE
RNA
TRACER TECHNIQUES
TRITIUM COMPOUNDS